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Digitized  by  the  Internet  Archive 

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http://www.archive.org/details/prostheticarticuOOclap 


Prosthetic 
Articulation 

BY 

George  Wood  Clapp,  D.D.S. 


wmMTTimmm^ 


PUBI.ISHF.I)    BY 

THE  DENTISTS'  SUPPLY  COMPANY 

220  Wpist  42nd  Sirilet 
New  York 


..I 


Copyright  1914 

BY 

George  Wood  Clapp,  D.D.S. 


PREFACE. 

Tliis  book  is  intended  to  make  plain  the  principles  of  impression 
taking  and  prosthetic  articulation,  but  not  to  cover  all  applications  of 
those  principles  or  to  explain  everv  minute  detail  of  technic. 

What  is  here  presented  has  been  learned  from  many  sources.  I 
wish  to  disclaim  originality  in  connection  with  anything  appearing  in 
the  book,  and  to  express  my  thanks  to  all  who  have  aided  in  any  way. 
Especial  thanks  are  due  to  three  helpers,  as  follows: 

^Ir.  S.  G.  Supplee  taught  me  the  method  of  taking  impressions 
and  helped  in  preparing  this  presentation.  He  follows  Dr.  Greene's 
method,  but  has  effected  important  improvements  in  finishing  the  im- 
pressions with  the  mouth  closed  and  under  normal  biting  stress.  For 
this  reason  I  have  called  the  method  herein  described  the  Greene-Supplee 
method.  Impressions  finished  in  this  way  form  excellent  bases  for  re- 
cording mandibular  movements  by  Professor  Gysi's  methods. 

Dr.  J.  Leon  Williams  has  permitted  the  use  of  his  methods  of  se- 
lecting porcelain  tooth  forms.  I  believe  these  to  be  the  first  really  scien- 
tific methods  of  selecting  tooth  forms  ever  offered.  By  means  of  them 
a  person  untrained  in  dentistry  can  select  tooth  forms  better  than  has 
heretofore  been  possible  to  even  skilled  dentists. 

Professor  Gysi's  methods  of  articulation  seem  to  me  far  superior 
to  any  others.  They  demand  more  of  the  dentist  in  the  early  stages  of 
the  work  than  other  methods.  Put  they  yield  results  not  otherwise  ob- 
tainable.    And,  f)iice  mastered,  they  really  save  time. 

(Jysi  articulators  and  Trubyte  teeth  are  described  and  illustrated 
hci-e  because  I  believe  them  to  be  unapproached  by  any  other  products 
in  their  respective  lines. 

The  Authoj-. 


Table  of  Contents 


PART  I 

Impression  Taking 

The  Object  in  Impression  Taking,  11;  Nausea  from  Dentures,  11; 
Impression  Material,  12;  Essential  Steps  in  Impression  Taking,  12; 
Examining  tlie  Moutli,  12;  Positions  of  Upper  Buccal  Attacliments, 
14-15;  Guidance  by  Facts  Learned  During  Examination  of  the  Mouth, 
16;  Chart  for  Artificial  Dentures,  17;  Impression  Trays,  18-19;  Warm- 
ing the  Compound,  2  0-21;  Attaching  the  Compound  to  the  Tray,  20-21; 
Shaping  the  Compound  for  the  Impression,  22-23;  Shaping  the 
Compound  for  an  Upper  Impression,  24-27;  The  Upper  Baseplate 
Impression — Trimming  the  Bite,  28-35;  Taking  the  Lower  Baseplate 
Impression,  3  6-3  9;  Making  the  Baseplate  Impressions  into  Trial  Plates, 
40-42;  Recording  the  Bite,  43-45;  Building  up  the  Margins  of  the 
Upper  Impressions,  4  6-47;  Massaging  the  Margins  of  the  Upper  Im- 
pressions, 48-49;  Condensing  the  Upper  Buccal  and  Labial  Attach- 
ments, 50-51;  The  Antero-posterior  Length  of  the  Upper  Impression, 
52-53;  Adapting  the  Upper  Impression  to  the  Palatal  Soft  Tissues 
— The  Effect  of  Adaptation,  54-5  7;  Essentials  of  Comfort  in  a 
Lower  Denture,  58;  Finishing  the  Lower  Impression,  59;  Taking  Partial 
Impressions,  60-61;  Points  to  be  Remembered  in  Refitting  Upper  Plates 
or  in  Taking  New  Impressions,  62-63. 

PART  II 

Selecting  The  Forms  And  Sizes  In  Anterior  Teeth 

Foreword,  67;  The  Origin  of  Face  Forms  and  Tooth  Forms,  6  8-69; 
Harmony  Between  Facial  Forms  and  Tooth  Forms,  70-71;  The  Tem- 
peramental Theory  of  Tooth  Forms — The  Application  of  these  Discov- 
eries to  Porcelain  Teeth,  72-75;  Determining  the  Type  of  Face  and 
Teeth,  76-77;  Modifications  of  the  Square  Type  of  Face,  78-79;  Modifica- 
tions of  the  Tapering  Type  of  Face,  80-81;  Modifications  of  the  Ovoid 
Type  of  Face,  82-83;  Modifications  of  the  Square  Type  in  Teeth  (Class 
I),  84-85;  Modifications  of  the  Tapering  Type  of  Teeth  (Class  II),  8  6-87; 
Modifications  of  the  Ovoid  Type  of  Teeth  (Class  III),  88-8  9;  Selecting 
Anterior  Teeth  of  Proper  Sizes,  90-94;  Determining  Width  of  the  Full 
Set,  94-96;  Selecting  Teeth  for  Partial  Cases,  Bridges  and  Crowns,  97; 
Selecting    Lower    Teeth,    97. 


PART  III 

Colors  In  Natural  And  Artificial  Teeth 


Foreword,  101;  The  Color  Scheme  in  Natural  Teeth,  102;  How  Color  in 
Natural  Teeth  was  Studied,  103;  Color  Analysis,  104-108;  How  the 
Colors  are  Placed  in  Natural  Teeth,  109;  The  Vagaries  of  Color  in 
Natural  Teeth,  110-111;  Colors  and  Shades  in  Ordinary  Artificial  Teeth, 
112;  Colors  and  Shades  in  Trubyte  Teeth,  113;  Suggestions  for  Select- 
ing Colors  and  Shades,  114;  Table  of  the  Colors  in  the  Twentieth  Cen- 
tury Shade  Guide,  115;  Enamel  Markings  in  Natural  and  Porcelain 
Teeth,  116. 


PART  IV 

Efficiency  In  Bicuspids  And  Molars 


Foreword,  119;  Functions  of  the  Natural  Bicuspids  and  Molars,  12  0- 
121;  Modifications  of  Natural  Forms  Necessary  in  Porcelain  Teeth,  122; 
What  Constitutes  Depth  of  Bite,  122;  Five  Stages  of  Wear  of  Natural 
Teeth,  123;  The  Working  Bite,  124-126;  The  Balancing  Bite,  126-127; 
Proper  Formation  of  Cuspid  Edges,  128-129;  Cracking  and  Tearing 
Power  in  the  Bicuspids,  130-131;  Cutting  and  Grinding  Power  in  the 
Molars,  132-133;  The  Impossibility  of  Grinding  Improperly  Formed 
Teeth  to  Proper  Bites  or  to  Efficient  Forms,   134-135. 


PART  V 
The  Selection  Of  An  Articulator 

Foreword,  139;  Selecting  an  Articulator,  141;  How  the  Jaw  Movements 
were  Recorded,  142;  Recording  Opening  and  Closing  Movements,  142- 
143;  The  Importance  of  the  Records  of  the  Opening  and  Closing  Move- 
ments, 144-14  5;  The  Practical  Importance  of  Correct  Opening  and 
Closing  Movements,  146-147;  Recording  Lateral  Movements  of  Condyles 
and  Chin,  14  8-149;  The  Importance  of  the  Records  of  the  Lateral 
Movements,  150-151;  The  Practical  Value  of  the  Lateral  Movements, 
152-157;  The  Influence  of  these  Adjustments  on  the  Movements  of  the 
Bicuspids  and  Molars,  158;  Permit  Deeper  Underbite  of  Lower  Incisors, 
159;  Increase  the  Cutting  Power  of  the  Incisors,  159-160;  The  Gysi 
Adaptable  Articulator,  161-162;  The  Gysi  Simplex  Articulator,  163-165. 


PART  VI 

Mounting  The  Trial  Plates  On  The  Articulator 

Measuring  the  Patient's  Mandibular  Movements,  169-179;  Determin- 
ing the  Inclinations  of  the  Lateral  Path  of  the  Condyle,  180-181;  Meas- 
uring the  Inclination  of  the  Downward  Condyle  Paths,  182-184;  Pour- 
ing the  Models,  185;  The  Relation  of  the  Incisor  Point  to  the  Condyles, 
186-18  7;  Mounting  the  Models  on  the  Adaptable  Articulator,  18  8;  De- 
termining the  Horizontal  Locations  of  the  Rotation  Points,  188;  Attach- 
ing the  Models  to  the  Gysi  Simplex  Articulator,   190-193. 

PART  VII 

Articulating  The  Teeth 

Making  Wax  Trial  Plates,  19  6-197;  Setting  the  Anterior  Teeth,  198- 
201;  Relative  Widths  of  Upper  and  Lower  Anterior  Teeth,  2  02-2  03; 
Grinding  Anterior  Teeth  to  Form,  2  04-2  05;  Setting  up  the  Bicuspids 
and  Molars,  206-211;  Automatic  Articulation,  212-214;  Grinding  the 
Teeth  to  Finished  Articulation,  215-217;  Trubyte  Molar  Blocks,  218- 
219;  Waxing  Plates  to  Facilitate  Pronunciation,  22  0;  Investing  the 
Bicuspids  and  Molars,  220;  Articulating  the  Vulcanized  Dentures,  22  0. 


PART  VIII 

Illustrations  And  Descriptions  Of  Teeth 
And  Tables  Of  Dimensions 

Form   1 — Class  1 226-227 

Form  2 — Class  I.  .  . 228-229 

Form  3 — Class  1 230-231 

Form   4 — ^^Class  I .23  2-233 

Form  5 — ^Class  1 234-235 

Form   1 — ^Class   II 236-237 

Form   2 — Class   II 238-239 

Form   3 — Class   II 240-241 

Form   4 — Class   II 242-243 


PART    I 


Impression  Taking 


THE  OBJECT  IX  IMPRESSIOX  TAKING 

is  to  secure  models  over  which  to  make  dentures  that  exhibit 
Relative  stability  in  all  positions  of  the  mouth, 
Efficiency  in  speech  and  mastication,  and 
Comfort  to  the  patient. 


Impressions  finished  with  the  mouth  closed  facilitate  the  making  of 
such  dentures  for  the  following  reasons : 

When  the  mouth  is  opened,  the  soft  tissues  on  the  buccal  sides  of 
the  upper  ridge,  and  overlying  the  hard  palate  are  distended.  Im- 
pressions taken  with  the  mouth  open  yield  models  of  the  tissues  in 
distended  positions.  Dentures  made  over  such  models  are  often  not 
stable  in  all  positions  of  the  lips  and  cheeks. 

When  the  mouth  is  open,  the  two  prominent  bands  of  soft  tissue 
on  the  buccal  side  of  each  upper  ridge  are  distended  backward  from 
their  attachment  to  the  ridge.  For  want  of  a  better  term  I  have  called 
this  the  ''posterior  position."  When  the  mouth  is  closed  and  at  rest,  the 
anterior  band  occupies  what  I  have  called  the  ''^middle  position,"  while 
the  posterior  band  seems  to  lose  its  individuality. 

When  the  mouth  is  closed  and  the  lips  are  thrust  forward  as  in 
whistling  or  seizing  food,  the  anterior  band  occupies  what  I  have  called 
the  ''anterior  position."  The  posterior  band  is  rarely  prominent  in  this 
position. 

The  positions  of  these  bands  are  shown  in  Figures  2-3-4. 

If  the  buccal  margins  of  the  impression  are  trimmed  to  fit  these 
bands  in  the  posterior  position,  the  act  of  thrusting  the  lips  out  in  biting 
food  is  very  likely  to  dislodge  the  upper  denture.  But  if  the  margins  of 
the  impression  be  trimmed  to  fit  the  attachments  in  the  anterior  position, 
it  will  Ite  impossible  to  dislodge  the  denture  by  any  movements  of  the 
lips. 

Iiupix'ssions  with  properly  trimmed  margins  can  l)e  taken  only 
while  the  mouth  is  closed  and  the  upper  and  lower  impressions  support 
each  other  under  normal  l)iting  strain.  The  eU'ects  of  such  trimming 
are  shown  in  the  ilbistrations  on  page  15. 


NAUSEA  FKOM  DENTURES. 

Nausea  is  not  caused  by  a  properly  fitting  upper  denture  extending 
too  far  backward,  but  by  an  imperfect  fit  of  the  posterior  margin  of 
the  denture,  so  that  the  soft  tissues  in  moving  up  and  down  just  touch 
the  denture,  and  a  tickling  sensation  is  caused,  which  results  in  nausea. 

If  an  efiort  is  made  to  secure  a  fit  by  carving  the  model  so  that  the 
posterior  margin  of  the  denture  j)rosses  up  into  the  soft  tissues,  nausea 
may  result. 

If  the  impression  })e  finished  witli  the  mouth  closed  and  the  im- 
pressions under  normal  l)iting  strain,  the  upper  denture  may  be  carried 
as  far  l)ack  as  is  reqnircd,  witlif)ut  causing  nausea. 

11 


IMPKESSIOX  MATEEIAL. 

Modeling  compound  is  preferred  for  impression  taking  because : 

It  permits  taking  the  impression  in  "stages." 

Impressions  may  be  finished  with  the  moutli  closed  and  under  nor- 
mal biting  stress.  This  permits  such  adaptation  of  the  dentures  to  the 
soft  tissues  as  is  not  otherwise  possible,  and  seems  to  the  writer  the  most 
important  advance  in  impression  taking  methods  of  recent  years. 

The  dentist  may  know  from  the  impressions  whether  or  not  the 
dentures  will  fit  the  mouth. 

Minor  imperfections  in  the  impressions  can  be  easily  corrected. 

The  impressions  are  built  into  trial  plates.  This  expedites  den- 
ture completion. 

ISTone  of  these  procedures  is  practicable  with  plaster  of  paris. 


ESSENTIAL  STEPS  IX  IMFRESSIOIst  TAKIXG. 

Examining  the  moutli. 
Trimming  the  upper  and  lower  trays. 
Shaping  the  compound  in  the  trays. 
Taking  the  working  impressions. 
Making  upper  and  lower  trial  plates. 
Finishing  the  impressions. 


EXAMIXIXG  THE  MOUTH. 
Figure  Xo.  1. 

Every  mouth  should  he  examined  as  to : 

The  character  and  extent  of  soft  tissues  overlying  the  hard  palate. 

Where  the  movable  portion  of  the  soft  palate  begins. 

The  character  and  extent  of  soft  tissues  in  the  ridges. 

The  location  and  strength  of  the  muscular  attachments  on  the 
buccal  sides  of  the  upper  ridge  and  both  sides  of  the  lower  ridge. 

The  space  between  the  tuberosities  of  the  upper  ridge  and  the  rami 
of  the  mandible  when  the  mouth  is  closed. 

Examinations  should  be  made  with  the  finger,  with  the  mouth  open 
and  closed. 

All  unusual  conditions  should  be  recorded  on  a  chart.  They  may 
aid  in  making  the  dentures  or  in  satisfying  the  patient. 

The  chart  used  at  the  Gysi  School  of  Articulation  is  reproduced 
on  page  17.     It  follows  very  closely  Dr.  McLeran's  design. 

12 


I'iK.    1. 
Kxiiiiiiiilii;^    till-    iiioiitli    tiy    tlii'    Miil    of    the    linger. 


13 


POSITIONS   OF   THE   UPPER   BUCCAL^  ATTACHMEXTS. 

Figures  Xos.  2,  3,  4. 

The  darkened  areas  in  Figure  2A  show  the  two  prominent  bands 
of  tissue  attached  to  the  buccal  side  of  the  upper  ridge,  in  the  position 
they  occupy  when  the  mouth  is  wide  open.  I  call  this  "the  posterior 
position."     Both  bands  are  prominent. 

The  blackened  area  in  Figure  2B  shows  the  position  occupied  by 
the  anterior  band  when  the  mouth  is  closed  and  the  tissues  are  relaxed. 
I  call  this  "the  middle  position."  Under  this  condition  the  posterior 
band  seems  to  lose  its  definition  and  merge  into  the  other  tissues. 

When  the  lips  are  projected,  as  in  whistling  or  taking  food,  the 
anterior  band  moves  forward  with  its  attachment  to  the  ridge  as  a 
center,  to  what  I  call  "the  anterior  position."  This  position  cannot 
be  easily  shown  in  a  model  but  its  influence  on  the  margin  of  an  impres- 
sion can  be  seen  in  Figure  31C.  The  posterior  band  does  not  seem  to 
be  prominent  in  this  position. 

The  Greene-Supplee  method  of  impression  taking  allows  both  bands 
to  "trim"  the  buccal  margin  of  the  upper  impression  to  all  of  their 
positions,  and  then  condenses  the  margin  against  the  buccal  tissues  with 
the  mouth  closed,  the  muscles  relaxed,  and  the  anterior  band  in  middle 
position.  Dentures  thus  "muscle  trimmed"  are  generally  stable  in  all 
positions  of  the  mouth. 

Figure  3A  shows  a  model  of  a  mouth  with  the  tissues  in  the  pos- 
terior position  and  a  metal  plate  adapted  to  it.  Figure  3B  shows  a 
model  of  a  mouth  made  with  the  buccal  tissues  relaxed  in  middle  posi- 
tions, and  the  same  metal  plate  on  it.  The  space  between  the  model 
and  the  margin  of  the  plate  is  noticeable. 

Figure  4A  shows  a  plaster  impression  of  a  lower  jaw,  as  usually 
taken.  There  is  a  great  excess  of  material,  which  has  distended  the 
tissues  on  both  sides  of  the  ridge.  This  distension  prevents  the  adapta- 
tion of  the  margins  of  the  denture  to  the  tissues  at  the  base  of  the  lower 
ridge.  Such  adaptation  is  essential  to  comfort  and  efficiency  in  a  lower 
denture. 

Figure  4B  shows  a  lower  impression  taken  after  the  Greene-Sup- 
plee method  and  properly  adapted  to  the  tissues  at  the  side  of  the  ridge. 
This  impression  is  comfortable  and  relatively  stable  in  all  positions  of 
the  mouth. 

14 


Fig.  2. 


Fig.  3. 


Fig.  4, 
15 


GUIDAXCE  BY  FACTS  LEARI\TED  DURI^s^G  EXAMI]^ATI0X 

OF  THE  MOUTH. 

The  upper  denture  should  extend  far  enough  back  of  the  hard 
palate  so  that  its  margin  will  make  a  valve  with  the  soft  tissu-es.  In 
cases  of  firm  ridges  in  the  front  of  the  mouth,  the  denture  need  not 
extend  back  onto  the  movable  soft  tissues.  When  the  ridge  in  front  is 
very  soft,  the  denture  must  extend  farther  Imckward  to  prevent  being- 
thrown  down  in  biting. 

Care  must  be  taken  not  to  displace  the  tissues  in  soft  ridges.  In 
cases  with  very  flabby  ridges,  special  steps  to  prevent  displacement 
must  Ije  taken.  Care  must  be  taken  also  not  to  stretch  the  tissues  on 
the  upper  surface  of  the  lower  ridge,  and  cause  pain. 

The  muscular  attachments  on  the  buccal  side  of  the  upper  ridge 
may  be  extensive  or  small,  and  strong  or  weak.  The  firmer  the  muscles, 
the  greater  care  must  be  taken  to  provide  for  their  accommodation  by 
the  margins  of  the  denture. 

The  muscles  on  both  sides  of  the  lower  ridge  must  be  accommo- 
dated. They  are  weak  but  effective  in  dislodging  a  denture.  Perhaps 
even  more  care  is  necessary  here  than  in  the  upper  denture.  In  cases 
with  narrow  lower  ridges,  the  lower  denture  may  need  to  ride  partly 
on  the  muscles.  But  it  must  be  evenly  raised  and  lowered  by  the 
muscles  during  movements  Avith  the  mouth  open,  and  not  thrown  out 
of  position. 

Care  must  be  taken  that  the  upper  tray  and  impression  are  so 
trimmed  between  the  tuberosity  of  the  upper  ridge  and  the  ramus  of 
the  lower  jaw,  that  the  denture  shall  not  cause  congestion  of  the  tissues. 

Spots  of  very  hard  tissue  overlying  the  hard  palate  must  be  re- 
lieved by  laying  tin  of  proper  thickness  over  the  model  just  before 
vulcanizing.     This  applies  especially  to  the  tissues  of  the  .median  line. 


16 


Chart  for  Artificial  Dentures 

(after  that  compiled   by  J.    W.    McLERAN.   OMAHA.  NEB.) 


Name 


Address. 


MEMBRANE 


ARCH    AND    VAULT. 

INFLAMED  HIGH.  FLAT.  OVAL.  FRESH. 

REGULAR 

Firm. 


PERMANENT. 


FLABBY 

SUBMUCOUS 

TISSUE. 


ABNORMAL 

MUSCULAR     OR 

GLAND.    ATTACHMENT. 


LATERAL 
CONDYLE  PATHS. 


FORWARD 
CONDYLE   PATHS. 


^  ^  RIGHT 


BONY     PROMINENCE. 


UNDERCUT. 


ROTATION  POINTS   OUT 
FROM  CENTER 


Right   at   No. 


SELECTION     OF    TEETH. 


M  EASUREMENTS 


UPPER 
MOULD 
NUMBER 


-MM.  LENGTH    OF   CENTRAL    INCISORS. 

-MM.  Combined    Bite    and    Shut 
MM.  Rioge    Lap. 

MM.  Width    6    Anteriors 

-MM.  Width    Full    Set.    id. 


MM.         I 


MM 

LOWER 

MOULD 

MM. 

Shade   Upper  Central- 


Kind    OF    TEETh 


l''iKlir«  ^ 


17 


IMPKESSIOis^  TRAYS. 

The  trays  here  illustrated  are  those  designed  by  Dr.  Greene.  Those 
designed  by  Mr.  Supplee  are  more  convenient  in  some  respects.  Other 
trays  can  be  used  by  proper  trimming,  and  are  used  by  some  followers 
of  this  method. 

Trim  the  upper  tray  for  antero-posterior  length  first.  If  the  alveolar 
ridge  in  the  anterior  portion  of  the  upper  jaw  was  found  to  be  hard, 
trim  the  center  of  the  posterior  margin  to  rest  on  the  soft  tissues  imme- 
diately posterior  to  the  margin  of  the  hard  palate.  If  the  ridge  was 
soft,  trim  the  tray  to  extend  back  a  little  way  onto  the  tissues  which  can 
be  seen  to  vibrate  when  the  patient  opens  the  mouth  and  says  "Ah." 

Bend  the  posterior  margin  of  the  tray  to  lie  in  easy  contact  with  the 
tissues  from  the  ridge  on  one  side  to  the  ridge  on  the  other. 

Trim  the  buccal  margins  of  the  tray  until  they  ''clear '  all  muscular 
attachments,  so  that  the  patient  cannot  bring  any  pressure  on  the  tray 
by  lip  or  cheek  movements.  Bend  these  margins  so  that  they  follow 
the  outer  sides  of  the  ridge,  about  Ys  inch  away. 

The  upper  tray,  as  thus  trimmed,  will  be  "shorter"  in  all  direc- 
tions, than  the  impression  is  to  be.  This  permits  manipulation  of  the 
margins  of  impression  material,  where  they  extend  beyond  the  margins 
of  the  tray. 

Trim  the  height  of  the  "heels"  of  the  buccal  margins  according  to 
the  amount  of  free  space  between  the  tuberosity  of  the  upper  jaAv  and 
the  ramus  of  the  lower. 


Trim  the  labial  and  buccal  margins  of  the  lower  tray  until  it  can- 
not be  dislodged  by  lifting  the  cheeks  and  lips. 

Trim  the  inner  margin  until  lifting  the  tongue  does  not  dislodge  it. 

The  tray  as  thus  trimmed  may  be  extremely  narrow.  This  need 
not  cause  apprehension.  The  only  function  of  a  lower  tray  is  to  carry 
the  compound  to  place. 


Bend  the  handles  of  both  trays  out  of  the  way  of  the  lips. 
Dry  both  trays  to  receive  compound. 

18 


Fig.    6 

A.  A  Greene  tray,  untrimmed  for  lielglit  or  length  and  not  tittt'd  to  tlie  curvature  of 
tbe  vault  or  ridge.  This  tray  is  likely  to  distend  the  tissues.  It  locates  the  posterior 
margin  of  the  denture  without  reference  to  the  conditions  in  the  mouth.  It  prevents 
adaptation  of  the  impression  margins  at  all  the  borders. 

B.  An  excess  of  compound  arranged  with  more  care  tliaii  is  custoin.-iry,  in  the  tray 
shown   in   "A."     Note   the  thickness   of  compound   at   the   posterior   margin    of   the   trny. 

C.  The  impression  taken  with  the  tray  and  compound  shown  in  "A"  and  "B."  Tiiis 
compound  was  evenly  hot  throughout  the  mass.  The  posterior  margin  of  the  tray  has 
come  into  contact  with  the  tissues  at  two  spots,  while  the  center  of  this  margin  was  too 
far  from  the  tissues.  This  iniijression  was  taken  witli  the  mouth  open  and  without 
"muscle  trimming." 


Fig.   7 

A.  The  same  tray  as  is  Hhown  in  OA,  but  trimmed  for  length,  and  bent  to  easy 
contact  with  the  tisHues  of  the  vault  at  ttie  posterior  margin.  The  buccal  and  labial 
tnargins  trimmed  to  "clear"  all  muscles  and  to  follow  tli(!  curvafui-e  oC  (lie  ridge.  'I'his 
tray  permits   maniiiulation   of  all   lmt)resslon    margins. 

B.  About  the  right  amount  of  (•om|)ouMd,  projierly  arranged  in  tray.  Note  tliat 
tbe  compound  does  not  extend   rjulte  to  tlie   rear  margin  of  tlie  tray  iu    tlie  median  line. 

C  A  basefilate  Imiiresslon  from  the  same  mouth  as  the  irnpiessioii  In  fiC.  The 
DiaMHage  Illustrated  In  i'"lg.  17  has  been  applied.  This  inroiiiiilcic  iiiipicssiou  is  better 
than   the  supposerlly  comidete  one  in    l''lg.  (!<'. 


19 


WAEMIJSTG  THE  COMPOUND. 

rigure  jSTo.  8. 

Less  than  half  a  sheet  of  compound  is  usually  sufficient  for  an 
upper  impression  of  ordinary  size.  The  more  skillful  the  operator  the 
less  compound  he  requires. 

The  compound  is  to  he  immersed  in  hot  but  not  boiling  water,  and 
heated  until  the  sharp  margins  begin  to  round  down.  It  should  then 
be  kneaded  until  the  mass  is  of  equal  softness  throughout. 

If  the  fingers  are  kept  wet,  the  hot  compound  will  not  stick  to  them. 

If  the  vessel  containing  the  water  is  heated  from  below,  a  piece  of 
blotter  may  be  laid  in  the  bottom  to  prevent  the  compound  sticking  to 
the  dish.  If  the  blotter  extends  above  the  water  on  two  sides,  it  will 
be  useful  in  lifting  the  compound. 

Electric  heaters  which  heat  the  upper  surface  of  the  water  more 
than  that  in  the  bottom  of  the  dish  may  be  had,  and  are  advantageous. 

Form  the  soft  compound  into  a  smooth  l^all. 


ATTACHING  THE  C0MP0U:N^D  TO  THE  TEAY. 
Figure  iSTo.  9. 

Heat  one  side  of  the  compound  above  a  tiny  gas  flame  or  an  alcohol 
flame  until  it  sizzles. 

Attach  the  sizzling  side  to  the  center  of  the  dry  upper  tray. 


20 


Less  than  half  a  sheet  of  (•onipound  is  reciuired  for  an  upper  impression  of  niedluni 
size.  It  is  heated  in  water  of  a  temperature  of  about  160°  until  the  sharp  margins  be^'in 
to  round.  It  should  be  kneaded  until  it  is  an  even  softness  throughout  the  mass  and 
shaped  into  a  ball. 


rig.  ;• 

'JIh!  upper  ImpreKsioii  tray  Is  dried.     One  siih-  of  the  ball  of  ciiiripipiiiid  is  heated  over  the 
flame  until  It  hIz/Jch  uikI  Im  at  onee  attached  to  the  citiiU-i-  of  the  vault  of  the  drii^d  tray. 


21 


SHAPmO  THE  COMPOUND  FOE  THE  IMPRESSIOK 
Figure  JSTos.  10  and  11. 

With  wet  fingers  quickly  shape  the  soft  compound  into  a  mound  in 
the  center  of  the  tray,  a  depression  all  along  where  the  alveolar  ridge 
will  come,  and  a  relatively  high  ridge  to  go  up  under  the  lip  and  cheeks. 

Do  not  allow  the  compound  to  extend  quite  to  the  posterior  border 
of  the  trav. 


The  compound  is  shaped  as  described  above  to  cause  it  to  come  first 
into  contact  with  the  tissues  as  shown  in  Figure  11.  It  should  strike 
first  the  centre  of  the  vault  of  the  palate,  and  the  labial  and  buccal  sides 
of  the  ridge,  and  flow  from  both  directions  to  the  alveolar  border.  In 
this  way,  distortion  or  displacement  of  soft  ridges  is  avoided  and  perfect 
impressions  obtained. 

When  the  ridge  is  extremely  soft,  that  portion  of  the  working  im- 
pression which  came  into  contact  with  the  soft  ridge  tissues  may  be 
cut  away,  very  soft  plaster  flowed  into  that  portion  of  the  tray,  and  the 
impression  replaced  in  the  mouth.  In  this  way,  impressions  of  very 
soft  ridges  tnay  be  obtained. 

Care  must  be  taken  not  to  push  forward  the  ridge  in  the  anterior 
13art  of  the  mouth,  or  pain  mnj  result  from  pressure  on  the  blood  ves- 
sels and  nerves  passing  through  the  anterior  palatine  canal  in  the 
median  line,  just  back  of  the  incisors. 

When  taking  the  lower  impression,  the  tissues  on  top  of  the  ridge 
must  not  be  stretched  or  pain  will  be  caused. 


22 


ViSX.    10 

Willi  wet  tiiifrors  sli:i|ic  the  ball  of  compound  to  iireseiit  a  trough  where  the  alveolar 
ridge  will  come,  a  higli  ridge  to  go  up  under  the  lip  and  cheeks  and  a  mound  in  the 
center  of  the  vault.  I>o  not  allow  the  compound  to  extend  (luite  to  the  posterior  margin 
of  the  tray. 


Tin-  compound  Is  Intendr-d  t 
and  laldnl  sides  of  the  ridge  and  t^ 
Hideti.  'i'lils  prevents  condensation 
buccal  margins  of  the  tray  are  low 


Fig.  n 

sirikc    lirsl    I  Ik 


center    of   the    vault    an<l    on    the    buccal 
Ib.w   tri  the  crest  of  the   riilge   by   [ii-essure   from   both 
or   disphiicment   of  even    soft    ridges.      Note   that    the 
■r  than   the  margins  of  the  impression   will  be. 

23 


SHAPING  THE  COMPOUND  FOR  AN  UPPER  IMPRESSION 

• — Continued. 

Figures  Nos.  12  and  13. 

Draw  the  compound  into  a  hill  which  shall  come  in  the  center  of 
the  vault.  If  there  is  more  compound  than  is  likely  to  be  required,  it 
can  be  pinched  off  as  shown  here.  Keep  the  compound  from  extending 
to  the  posterior  margin  of  the  tray. 

Warm  the  ''hill"  of  compound  over  a  gentle  flame  so  that  its  top 
shall  round  down,  but  shall  still  present  a  higher  cone  than  will  1)e  re- 
quired by  the  formation  of  the  vault. 


24 


^ 


^^ 


K' 


Fig.   12 

Shape  the  (■ompduiul  iiitu  tlie  fdrin  of  a  hill  in  the  center  of  tlie  tray.     Keep  it  warm  dvcr 

tlie  tlanie  and   plmh   oft'  any  excess  at  the  top  of  the  hill. 


Kit,'.  13 
When  tlu-  coiiipoiind  has  been  propci-l.v  shajiod  and  the  c.m'css  pinched  off,  warm  the 
top  of  the  liill  over  the  flame  so  that  it  i-aii  he  shaped  down  to  a  smo(j|h  surface.  Then 
I>aHs  the  entire  Iniprr-ssirin  siirfaic  of  tlic  '(iiiipoiiiid  ahovc  a  small  llamc,  so  tliat  tlic 
Knrf;i<'e  nia.v  be  rendered  softer  Iharj  I  lie  iinderl  \  In;,'  portions.  |)i|i  IIm>  Ir.iy  and  idmiHinnd 
into   hot   water  to  erjnalixe   the   heal. 

25 


SHAPI:NG  the  COMPOU^^D  for  A'N  upper  IMPRESSIOK 

Eiffures  jSTos.  14  and  15. 


'^fci" 


When  tlie  top  of  the  "hilF'  of  componnd  has  been  properly  warmed 
over  the  flame,  dip  the  entire  tray  into  hot,  but  not  boiling  water,  to 
equalize  the  heat  and  avoid  burning  the  patient. 

When  the  heat  has  been  equalized  in  this  manner,  it  is  desirable 
to  heat  the  surface  of  the  compound  more  than  that  which  lies  deeper  in 
the  tray,  so  that  the  surface  shall  be  in  condition  to  ^'flow"  easily  and 
shall  be  supported  by  the  slightly  cooler  compound  between  what  may 
be  spoken  of  as  "the  surface  layer"  and  the  tray. 

This  additional  heating  of  the  surface  compound  may  be  effected 
by  turning  the  tray  so  that  the  palatal  surface  is  downward  and  in  this 
position  immersing  the  margins  of  compound  and  the  "hill"  in  water, 
of  a  temperature  about  160  degrees,  but  not  immersing  the  tray. 

The  tray  should  then  be  quickly  inserted  into  the  mouth,  since  the 
surface  will  be  in  the  finest  possible  condition  for  impression  taking. 


26 


Fig.  1-i 
It  is  a  principle  of  tliis  method  of  Impression  taking  tbat  the  surface  of  the  compound 
shall  be  as  soft  as  may  be  without  changin.i;  form,  while  the  underlying  portions  of  the 
compound  shall  be  slightly  cooler  apd  firmer. 

When  the  surface  has  been  heated  as  described  and  the  heat  has  been  equalized, 
the  tray  may  be  held  with  the  impression  side  down  and  the  hill  and  margins  of  the 
innpression  immersed  for  a  little  in  hot  water.  The  tray  should  not  be  immersed. 
AVhen  it  is  removed,  the  surface  should  be  just  ready  to  flow,  while  the  underlying 
portions  of  compound  will  not  be  (|uite  so  soft.  The  tray  is  then  quickly  inserted  in 
the  mouth. 


27 


THE  UPPER  BASEPLATE  IMPEESSIOX. 

Figure  I^o.  15. 

Tlie  tray  is  passed  into  the  mouth  and  pressed  about  half  way 
"home"  with  a  slight  wave-like,  side  to  side  motion.  The  compound 
on  the  buccal  and  labial  surfaces  of  the  ridge  is  pressed  upward  and 
against  the  ridge  by  putting  the  finger  into  the  mouth  as  here  shown. 

This  carries  the  compound  against  the  ridge  and  higher  than  the 
margins  of  the  impression  will  finally  be.  It  makes  possible  the  proper 
trimming  of  the  margins  by  the  muscles. 

If  the  compound  is  not  carried  up  by  the  finger,  the  margins  of 
the  impression  may  be  deficient,  and  much  of  the  value  of  this  method 
may  be  lost. 


28 


('iin-y\lii;  tlio  coiiiiioiiimI    ii|<   iiiiilci-   tln'   lip  nnd    rlicck.s   to   iiism-c   siillicifiilly    lii;,Mi    rims. 

29 


THE  UPPER  BASEPLATE  IMPRESSI0:N'— Continued. 
Figure  JSTo.  16. 

While  the  cup  is  being  pressed  ^'home,"  have  the  patient  draw  back 
the  lips  as  in  hearty  laughing  and  then  push  them  well  out,  as  in  the 
position  for  whistling.  These  motions  of  the  cheeks  and  lips  call  into 
action  the  muscles  which  extend  over  the  margins  of  the  impression, 
and  enable  them  to  shape  the  compound  to  forms  which  will  accom- 
modate their  movements  without  dislodging  the  denture.  That  is, 
the  muscles  ''trim"  the  margins  of  the  impression.  The  importance  of 
this  will  be  more  apparent,  later. 

The  necessities  of  illustrating  the  action  of  the  upper  lip,  required 
the  dentist  to  stand  well  back  for  this  picture.  In  practice,  it  is  im- 
possible to  stand  back  in  this  way  and  hold  the  hand  so  far  back  with- 
out rocking  the  impression,  which  will  cause  the  denture  to  rock  also. 

The  dentist  must  stand  in  front  of  the  patient,  must  see  that  his 
finger  extends  well  back  under  the  tray,  must  press  the  tray  up  at  the 
back  first,  and  when  it  is  in  position,  must  hold  it  firmly  against  the 
palate,  with  just  the  slightest  forward  pressure  to  carry  it  toward  the 
highest  part  of  the  vault. 

The  patient  will  probably  make  the  lip  motions  more  intelligently 
if  the  dentist  instructs  the  patient  how  to  make  them  before  commencing 
impression  taking,  and  if  he  makes  them  when  he  directs  the  patient  to. 


30 


Patient    "musck'-trlriiinliiK"    upper    imprcssiDii    by    Hi)    iiiovciiH.'iits. 


31 


THE  UPPEK  BASEPLATE   IM PEE SSIOJN'— Continued. 

Figure  jSTo.  17. 

Wlien  the  compound  was  pressed  up  under  the  lip  and  cheeks  as 
shown  in  Figure  13,  it  was  carried  higher  than  the  margin  of  the  im- 
pression will  be,  in  order  that  it  might  be  trimmed  by  the  action  of  the 
muscles. 

The  motions  of  the  cheeks  and  lip  shown  in  Figure  17  trimmed 
the  margins  of  the  comjDOund,  by  turning  it  outward  and  downward 
where  it  interfered  with  their  movements.  In  doing  this,  they  fre- 
quently turn  it  too  far  downward,  and  it  is  necessary  to  press  it  inward 
against  the  tissues  and  carry  it  again  a  little  upward. 

These  ends  can  be  achieved  by  applying  the  thumb  and  forefinger 
■oi  the  left  hand  to  the  cheeks  and  lip,  heloiv  the  upper  margin  of  the 
tray,  and  giving  them  a  slight  rotary  motion,  with  gentle  inward  pres- 
sure. Care  must  be  taken  not  to  pull  downward.  The  tray  is  mean- 
time held  firmly  in  position  by  the  finger  of  the  right  hand  in  the  vault. 

This  massage  will  also  continue  the  downward  movement  of  the 
excess  compound  and  turn  it  beneath  the  tray. 

When  this  massage  has  been  completed,  an  impression  should  be 
;sufiiciently  well  adapted  to  the  vault  of  the  mouth  and  the  surface  of 
the  ridges  so  that  it  will  not  rock.  If  it  rocks,  it  must  be  corrected  or 
remade,  since  the  rocking  will  invariably  lead  to  trouble. 

As  a  general  thing,  an  impression  which  has  been  carefully  taken, 
this  far,  will  have  also  enough  of  what  Dr.  Greene  calls  "sticktion"  to 
permit  its  use  in  the  later  stages  of  impression  taking. 


N 


32 


Fit,'.  17 
I"ir>t     iii;iss;ijrf,    Ix'Idw    npiicr    iii;ir;;iii    (if    tray. 

33 


TRIMMK^^G  THE  UPPER  BASEPLATE  IMPRESSION 

Figures  N^os.  18  and  19. 

The  margins  of  the  impression,  as  it  first  comes  from  the  mouth, 
are  generally  thick  enough  to  distend  the  tissues  of  the  cheeks  and  lips, 
a  condition  which  must  be  avoided. 

Trim  the  buccal  and  labial  margins  after  the  manner  shown  in 
Figure  'No.  18,  until  they  are  of  the  thickness  desired  in  the  finished 
denture,  and  give  the  patient's  face  the  desired  expression.  Care  should 
be  taken  not  to  alter  the  form  of  the  margins  or  to  break  the  compound. 
If  the  compound  is  broken  in  trimming,  no  effort  should  be  made  to 
repair  it  until  after  the  bite  is  taken.  Efforts  to  repair  it  before  that 
stage  is  reached,  usually  result  in  spoiling  the  impression.  If  the 
posterior  margin  of  the  impression  cup  was  exposed  in  taking  the  im- 
pression, it  should  be  bent  backward  out  of  contact  with  the  tissues. 
The  exposed  area  will  later  on  be  covered  with  compound. 

In  trimming  the  labial  and  buccal  margins,  much  care  should 
be  taken  to  restore  the  expression,  especially  in  the  region  of  the  canine 
eminences.  Figure  19  shows  a  patient  without  trial  plates  and  again 
with  properly  built  trial  plates. 

The  posterior  margin  of  the  impression  should  be  trimmed  to  the 
exact  length  desired  in  the  finished  denture.  When  the  alveolar  ridge 
in  front  is  hard,  the  denture  will  extend  on  to  the  relatively  immovable 
soft  tissues  immediately  posterior  to  the  hard  palate.  When  the  an- 
terior alveolar  ridge  is  soft,  the  denture  will  extend  back  onto  the  mov- 
able soft  tissues. 

The  "heels"  of  the  buccal  margins  should  be  trimmed  thin,  so  that 
they  will  not  distend  the  cheeks,  and  so  that  they  can  be  warmed  and 
massaged  into  the  desired  contact  with  the  tissues. 

The  possibility  of  softening  the  margins  and  adapting  them  by 
pressure  with  the  mouth  closed  and  the  impressions  supported  in  place 
under  normal  biting  strain,  constitutes  the  great  advantage  of  the 
G-reene-Supplee  method  of  impression  taking.  The  impression  is  now 
laid  aside  until  the  lower  impression  has  been  taken. 


34 


Trimming  impression  to  proper  buccal  and  labial  thickness. 


Fl(?.  19 
By  properly  flllln;?  out  and  "llftInK"  the  tlHsues,  great  changes  In  the  expression 

can    be    effected. 


35 


TAKIXG  THE  LOWER  BASEPLATE  IMPRESSIOK 

Figures  Nos.  20  and  21. 

Soften  the  compound  in  hot  bnt  not  boiling  water,  in  the  same 
manner  as  for  the  npper  impression.  Form  it  into  a  roll  about  half  as 
thick  again  as  a  lead  penciL  Lay  it  aside  to  cool  slightly  while  drying 
the  tray.  Heat  one  side  of  the  roll  over  a  small  flame  until  it  sizzles. 
Attach  this  side  to  tlie  dry  tray.  Pinch  oft"  the  excess  of  compound  at 
the  ends  of  the  tray.  Llold  the  tray  with  the  compound  side  up,  and 
immerse  the  tray  but  not  the  compound,  for  an  instant  in  cold  water. 
This  will  cool  the  tray  and  the  compound  next  to  it  and  cause  the  cooler 
portions  of  the  compound  to  act  as  a  tray  to  keep  the  softer  portions 
from  getting  too  far  out  of  place. 

Soften  the  surface  of  the  compound  over  the  flame  and  then  dip 
the  compound  but  not  the  tray,  into  hot  water  to  equalize  the  heato 
It  is  then  ready  for  prompt  insertion  into  the  mouth. 

For  lower  impressions,  the  compound  should  have  l^egun  to  cool 
a,  little  on  the  side  next  to  the  tray  as  mentioned  above  but  should  be 
ready  to  "flow"  on  the  surface.  If  the  compound  be  too  soft  all  the  way 
through,  the  tray  is  likely  to  come  into  contact  with  the  tissues  and 
cause  muscle  strain  and  an  imperfect  impression. 

If  the  tray  comes  into  contact  with  the  tissues,  it  must  be  cut  away 
at  the  exposed  points  until  it  is  lower  than  the  adjoining  compound. 


36 


Vig.  20 


as  th 


Shape  a  roll  of  compound  about  as  thick  again  as  an  ordinary  lead  pencil  and  as  long 
he  arcli  of  the  lower  tray.     Lay  it  aside  to  cool   a   little  while   drying  the  tray. 


Wiiriii  one  side  of  the  roll  till  it  sizj 
I'XiftHH  cdiiipoiinil  Jit  th<'  ends.  Snflcii  the 
fldiiie  until  It  Ih  nearly  rejidv  to  tluu,  |)ip 
'ouipouiid  next  to  It,  Into  liot  walir  l<>  !■■ 
the  mouth. 


the 
|ii;ili 


il    :itt:i< 

ssidii    s 

iprcssii 

the    Ik 


Il  It  l< 
iirCiU'c 
>ii   siirl'; 

■Ml.        It 


IIm' 
if    II 


ml    not 
Ihc'ii    re 


lr;iy.      I 'in 
ipoiiiid    iiv 

the   tr:iv 
•Mdy    to    pi 


■h  oir 
•r  I  he 
<\-  I  lie 


37 


TAKII^^G  THE  LOWER  BASEPLATE  IMPRESSION". 

Figure  'No.  22. 

Place  the  tray  and  compound  in  the  mouth  and  locate  them  di- 
rectly over  the  ridge,  or  a  little  to  the  lingual  of  the  anterior  part  of  the 
ridge.  When  they  are  properly  in  place,  have  the  patient  open  the 
mouth  as  wide  as  possible.  Stand  in  front  of  the  patient,  place  a  fore- 
finger on  the  bicuspid  region  of  each  side,  and  make  very  light  pres- 
sure on  the  tray.  If  the  tray  was  placed  a  little  to  lingual  of  the  ridge, 
this  pressure  can  be  slightly  forward  as  well  as  downward,  which  is 
an  advantage,  because  it  forces  the  excess  compound  to  flow  to  the 
lingual  side  of  the  ridge,  where  it  can  be  easily  controlled. 

Change  the  position  of  the  hands  so  as  to  bring  the  first  and  middle 
fingers  of  the  left  hand  on  the  two  sides  of  the  tray  in  the  bicuspid 
region,  and  hold  the  tray  steadily  in  place  with  very  light  pressure. 
Ask  the  patient  to  close  slightly,  so  as  to  relax  the  muscles.  Reach 
under  the  left  wrist,  and  with  a  thumb  and  finger  of  the  right  hand 
make  a  quick,  light  massage  on  the  outside  of  the  cheeks  in  the  region 
of  the  bicuspids  and  molars. 

Place  the  index  finger  of  one  hand  on  each  side  of  the  tray  in  the 
bicuspid  region,  and,  if  the  patient  is  sufficiently  intelligent  to  co- 
operate with  your  eft'orts,  ask  her  to  make  one  effort  to  SAvallow.  If  the 
patient  is  not  intelligent  and  might  bite  the  fingers,  ask  her  to  raise 
the  tongue  a  little.  The  contraction  of  the  muscles  in  swallowing  will 
begin  the  "trimming"  of  the  compound  on  the  lingual  margin  of  the 
impression. 

Remove  the  impression  from  the  mouth  and  trim  away  all  surplus 
compound  until  the  impression  is  smaller  than  the  lower  denture  is  to 
be.  This  impression  is  intended  only  to  lie  on  top  of  the  ridge  and 
serve  as  the  base  for  a  trial  plate.  Ho  corrections  should  be  attempted 
at  this  time  unless  the  impression  rocks.  If  the  impression  rocks,  it 
should  be  corrected  by  warming  the  entire  ridge  surface  evenly,  re- 
placing in  the  mouth  and  holding  down  with  light  but  firm  pressure. 
If  this  does  not  correct  it,  a  new  impression  should  be  taken. 


38 


Klg.  22 
Lo<ate  the  lower  tray  and  coinpoiiiKl  directly  over  or  a  little  to  the  lingual  of  the  ridge. 

.S9 


MAKING  THE  BASEPLATE  IMPEESSI0:NTS  INTO  TRIAL 

PLATES. 

Figures  Nos.  23  and  24. 

The  working  impressions  are  made  into  trial  plates  by  adding  a 
roll  of  componnd  to  each  and  trimming  it  to  indicate  the  positions  to 
which  the  teeth  are  to  be  set. 

Shape  a  roll  of  compound  a  little  larger  than  was  used  for  the 
lower  impression,  and  as  long  as  the  lower  ridge,  from  heel  around  to 
heeL  Heat  the  middle  portion  of  one  side  until  it  sizzles  and  attach  it 
to  the  anterior  portion  of  the  ridge  of  the  lower  tray,  leaying  the  ends 
free.  Direct  the  heat  of  a  tiny  flame  between  the  tray  and  the  unat- 
tached portion  of  the  roll,  and  when  each  end  is  hot  enough,  attach  it  to 
the  tray,  taking  care  to  keep  the  hands  moist  during  the  work. 

Shape  the  occlusal  edge  of  the  roll  to  the  form  of  a  wedge.  Soften 
the  wedge  deeply,  so  that  it  can  be  moulded,  and  quickly  place  the  trial 
plate  in  the  mouth.     Either  of  two  methods  can  now  be  followed. 

If  a  Gysi  Adaptable  x4rticulator  is  to  be  used,  press  the  Horseshoe- 
plate  which  comes  with  the  articulator,  into  the  lower  trial  plate  until 
its  labio-incisal  margin  is  about  1/16  inch  below  the  level  of  the  edge 
of  the  lip,  when  at  rest,  and  the  occlusal  surface  of  the  heel  is  on  a  level 
with  the  upper  surface  of  the  tulierosity  at  each  posterior  termination 
of  the  lower  ridge,  or 

Press  the  compound  of  one  side  to  the  same  level  with  a  short, 
straight  knife  blade,  like  that  of  some  plaster  spatulas.  Then  invert 
the  trial  plate  on  a  wet  piece  of  glass  and  by  pressure  shape  the  other 
side  to  the  same  level  as  the  pressed  side.     Trim  away  excess  compound. 

Trim  the  arch  of  the  lower  trial  plate  to  make  plenty  of  room  for 
the  tongue,  so  that  the  denture  will  not  be  lifted  by  the  tongue  being- 
crowded. 

Trim  the  buccal  margins  to  make  the  ridge  about  as  thick,  from 
tongue  to  lip  and  cheek,  as  the  teeth  will  be. 


40 


Fig.   2:;. 
Attaching  tlie  roll   tiniily  to  the  baseplate  iiiiiiressidii   t<<  I'onn  the  trial   plate. 


I'ig.    •_'!. 

A.  Lower  trial  jilato  with  horseshoe  phite  pressed  into  it.  I!.  Lower  trial  plate  with 
ridge  properly  forilU'd  without  use  of  liorseshoe  plati>.  Note  the  wide  space  lor  tonmic, 
the  shortened   "heels",  and   the  Corni   of   ridge. 


41 


MAKIN^G   THE   BASEPLATE   IMPRESSIONS   INTO    TRIAL 

PLATES— Continued. 

Attach  a  roll  of  compound  to  the  ridge  of  the  upper  impression 
in  like  manner,  shape  it  to  the  form  of  a  wedge,  place  it  in  the  mouth 
with  the  lower  trial  plate  in  position,  and  have  the  patient  close  the 
jaws  until  the  lips  nearly  touch  in  repose. 

Most  patients,  when  instructed  to  bring  the  jaws  together  till 
the  lips  touch,  stretch  the  lips  but  do  not  bring  the  jaws  close  enough 
together.  When  they  do  this,  the  lower  jaw  is  nearly  always  in  the 
retruded  position.  When  a  patient  does  this,  remove  the  upper  trial 
plate  from  the  mouth  and  trim  it  to  the  impression  made  in  its  occlusal 
surface  by  the  cold  lower  trial  plate.  Cut  away  the  "heels"  of  the 
ridges  of  both  trial  plates  as  far  forward  as  to  where  the  middle  of  the 
second  molars  will  come.  Warm  the  occlusal  surface  of  the  upper  over 
the  flame,  dip  into  hot  water  to  equalize  the  heat,  replace  in  the  mouth, 
and  have  the  patient  relax  all  muscles  and  then  close  the  jaws  until  the 
lips  touch  lightly  in  repose. 

This  determines  the  correct  heights  of  the  trial  plates,  equalizes 
the  pressure  on  both  sides,  which  is  most  important,  and  practically 
insures  a  correct  bite. 

For  some  years,  I  have  advocated  the  method  of  shaping  the  occlu- 
sal surface  of  the  upper  trial  plate  to  be  parallel  to  a  line  drawn  on 
the  face,  from  the  ear  to  the  nose.  Two  or  three  years  ago  Dr.  Ulsaver 
and  I  conducted  some  experiments  which  satisfied  us  that  the  location 
of  the  heels  of  the  occlusal  plane  could  be  moved  upward  or  downward 
somewhat  without  affecting  the  articulation  or  efficiency  of  the  teeth, 
and  sometimes  with  mechanical  advantage.  We  learned  later  that  Pro- 
fessor Gysi  had  conducted  similar  experiments  and  arrived  at  similar 
conclusions.  We  have  lately  followed  Mr.  Supplee's  modification  of 
the  method,  as  described  above,  and  find  it  easier  and  quicker. 


42 


EECOKDING  THE  BITE. 

Figures  Xos.  25,  26,  27,  and  28. 

"When  correct  biting  relations  have  been  established  bj  the  methods 
just  suggested  or  any  others  the  dentist  may  prefer,  it  is  important  to 
register  them  in  such  way, that  the  patient  will  be  compelled  to  bite  cor- 
rectly during  the  finishing  of  the  impressions,  since  a  wrong  bite  at  that 
time  may  destroy  all  accuracy  in  the  fit  of  the  impressions  and  subse- 
quently of  the  dentures. 

Dr.  Greene's  method  of  doing  this  is  probably  one  of  the  best.  It 
is  to  cut  a  notch  in  the  occlusal  surface  of  a  separate  trial  plate  at  the 
median  line,  and  one  at  each  side,  in  the  bicuspid  region.  The  occlusal 
surface  of  the  lower  trial  plate  is  then  dried  and  a  little  soft  compound 
added  to  it,  opposite  the  notches.  While  this  added  compound  is  still 
soft,  the  patient  is  caused  to  bite  in  right  position.  This  forms  three 
eminences  on  the  lower  trial  plate,  corresponding  to  the  depressions  in 
the  upper,  and  compels  the  patient  to  bite  in  right  relations  during  sub- 
sequent proceedings.  Mr,  Supplee  has  shortened  the  work  and  facilitated 
accurate  bite  taking  by  making  the  impressions  into  trial  plates  and 
using  tlic  notclies  in  the  same  way. 

This  method  demands  that  the  bite  be  accurate  when  the  notches 
are  filled  with  compound,  or  it  will  continually  thereafter  be  wrong. 

The  dentist  who  uses  the  Gysi  Adaptable  Articulator  has  the  most 
nearly  positive  method  of  determining  the  correct  closure  that  I  know 
of.  If  the  Incisor  Path  Register  is  used  in  connection  with  the  Horse- 
shoe plate,  1)lackened  in  front,  the  point  of  the  Register  will  trace,  in 
nine  cases  out  of  ten,  a  round  pointed  pattern  as  long  as  the  jaw  is 
protruded,  and  a  sharp  pointed  pattern  when  the  jaw  is  in  its  resting 
position.  This  record  alone  is  so  important  as  to  justify  the  use  of  this 
articulator,  for  dentures  and  extensive  bridges. 


43 


\ 


Fig.    25. 
Cutting   notches   in    the   lower   trial    plate   to    record    correct   biting    relations. 


Fig.   26. 

On  the  left,  the  trial  plates  as  bitten  together  in  the  mouth.     The  other  two  illustrations 

show  the  elevations  on  the  upper  trial  plate  and  the  notches  in  the  lower. 


Fig.    27. 

The  festoons  in  the  upper  trial  plate,  shown  on  the  right,  help  in  correctly  replacing 
the   trial   plates. 

The  vertical  marks  on  the  left  are  good,  while  the  sloping  marks  are  false  and 
misleading.     (Photograph  by  Prof.  Dr.  Gysi.l 

44 


liO'-onlllig  the;  l»itr.  I)y   iiic;iiis  of  tin-  (Jysl   Iii<-lsi>r  riitli    Iti-;,'istcr  aud   Ilorscslioe   J'late. 

45 


BUILDD^G  UP  THE  MAEGINS  OF  THE  UPPEK 

IMPEESSIOE'S. 

Figures  ISTos.  29  and  30. 

When  the  trial  plates  have  been  shaped  to  satisfactorily  support 
each  other  with  the  mouth  closed,  and  the  bite  has  been  taken  and  regis- 
tered, the  upper  impression  may  be  finished  under  normal  biting  strain. 
This  finishing  is  accomplished  by  modifying  the  margins  of  the  impres- 
sion to  conform  to  certain  positions  of  the  tissues. 

The  first  step  in  finishing  the  impression  is  to  make  sure  that  the 
margins  are  high  enough.  The  experienced  operator  will  be  able  to 
detect  low  places  in  the  margins  of  the  impression  at  a  glance,  but  the 
inexperienced  operator  cannot  do  this.  For  his  first  cases,  he  will  do 
well  to  add  compound  all  along  the  margins  by  heating  a  stick  of  com- 
pound and  building  onto  the  impression  as  shown  in  Figure  ISTo.  29. 
He  should  quickly  insert  the  impression  in  the  mouth,  the  lower  being 
alwaj^s  in  position,  have  the  patient  close  in  correct  bite  and  perform 
the  laughing  and  whistling  motions,  and  immediately  afterward  apply 
gentle  massage  as  illustrated  in  Figure  31. 

As  soon  as  the  margin  is  high  enough  all  around  and  has  been 
"muscle  trimmed"  and  massaged,  the  entire  buccal  and  labial  margin 
should  be  warmed  beside  a  small  flame,  until  the  compound  is  soft 
enough  to  permit  adaptation  by  massage,  but  not  soft  enough  to  change 
its  form.  The  impression  should  be  quickly  inserted  in  the  mouth,  the 
patient  caused  to  again  make  laughing  and  whistling  movements,  and 
the  compound  massaged  into  better  adaptation  to  the  buccal  and  labial 
tissues  in  the  manner  shown  in  Figure  31. 


46 


Fig.  29. 

Tracing   on    compound   from   a   stick    softened    over   the   flame   to    repair   broken    margin. 

Compound    for    building    up    margins    is    traced    on    the    side    of    the    impression 

in  contact  with  the  tissues. 


Fig.  ;jo. 

Softening   the   margins   without  clianging   their   form. 


47 


MASSAGING-  THE  MAEGIES  OF  THE  UPPER  IMPRESSIOI^. 

Figure  l^o.  30. 

Wiien  the  upper  trial  plate,  with  the  buccal  aud  labial  margius 
softened  as  described,  has  been  put  into  the  mouth,  and  the  lip  and 
cheek  movements  have  been  made  with  the  mouth  closed  and  the  trial 
plates  supporting  each  other,  and  the  j)atient  has  relaxed  all  muscle 
tension,  the  softened  margins  are  adapted  to  the  buccal  tissues  by  mas- 
sage. To  effect  this  massage,  the  finger  and  thumb  are  applied  first  to 
the  cheeks  and  then  to  the  lip,  on  the  level  of  the  softened  margins.  A 
gentle  inward  pressure  is  exerted  against  the  tissues,  and  the  thumb 
and  finger  are  given  a  slight  rotarv  motion. 

This  massage  is  not  intended  to  carry  the  compound  of  the  softened 
margins  either  up  or  down,  or  to  change  its  form,  but  merely  to  press 
the  already  formed  margins  inward  against  the  buccal  and  labial 
tissues,  while  the  attachments  to  the  buccal  side  of  the  ridge  are  in 
what  I  have  called  ''the  middle  position."  During  the  laughing  and 
whistling  movements  of  the  cheeks  and  lip,  these  attachments  have 
travelled  back  and  forth  under  the  margin  of  the  compound  and  have 
made  a  space  for  themselves.  When  the  patient  has  relaxed  all  mus- 
cular tension,  the  massage  will  adapt  the  margins  of  the  impression  to 
these  attachments  in  "the  middle  position."  EoUowing  such  adapta- 
tion, the  denture  will  be  stable  in  all  positions  of  the  lips  and  cheeks. 
Similar  light  massage  will  be  applied  to  the  margins  of  the  lower  trial 
plate. 

Some  ideas  of  the  possibilities  of  conformation  by  massage  may 
be  gained  from  Figures  31  and  32. 


48 


I    • 

r 


' 


via.  ■■;<). 

Flniil    iii!iss;iK<'   "f    iii:ir;:iiis   <>{    iipiicr    iniprcssidii.    iihovr   tlic   Ir.-iy. 


49 


CONDENSING  THE  UPPER  BUCCAL  AND  LABIAL 
ATTACHMENTS. 

Figures  Nos.  31  and  32. 

It  is  difficult  to  overstate  the  advantages  which  result  from  proper 
adaptation  of  the  margins  of  the  impressions  to  the  buccal  and  labial 
soft  tissues,  in  what  may  be  called  "the  middle  position."  The  several 
impressions  from  one  mouth  shown  in  Figures  Nos.  31  and  32  may  help 
to  make  the  possibilities  of  such  adaptation  clear. 

Figure  31A  is  an  impression  taken  with  a  poorly  adapted  tray, 
with  an  excess  of  compound,  and  with  the  mouth  wide  open.  The 
formation  of  the  margin  shows  the  buccal  attachments  to  be  in  the 
posterior  position. 

Figure  31B  shows  an  impression  of  the  same  mouth,  taken  with  a 
properly  adapted  tray,  a  correct  amount  of  compound,  and  "muscle 
trimmed"  with  the  mouth  open.  The  effect  of  the  muscle  trimming  on 
the  form  of  the  buccal  margins  is  very  marked. 

Figure  31C  shows  an  impression  of  the  same  mouth  which  has 
been  "muscle  trimmed"  with  the  mouth  closed  under  normal  biting- 
strain,  by  carrying  the  buccal  attachments  into  the  "anterior  position" 
in  the  whistling  movement,  but  without  adaptation  of  the  margins  by 
massage.  The  movement  of  the  buccal  attachments  into  the  "anterior 
position"  has  noticeably  altered  the  form  of  the  margin  from  the 
median  line  to  the  bicuspids. 

Figure  3 ID  shows  an  impression  like  that  in  33C  except  that 
after  carrying  the  buccal  attachments  into  the  "anterior  position"  the 
patient  relaxed  all  muscle  tension.  The  buccal  attachments  then  took 
the  "middle  position"  and  the  compound  was  adapted  to  them  in  this 
position.  Such  adaptation  seems  to  condense  the  buccal  attachments 
and  in  part,  to  destroy  their  definition,  since  they  do  not  cut  the  im- 
pression margin  to  anything  like  the  depth  shown  in  Figure  3lA,  B  or 
C.  This  impression  is  practically  perfect  and  cannot  be  dislodged  by 
any  movements  of  the  patient's  lips  and  cheeks.  After  failures  to  obtain 
satisfactory  dentures  at  the  hands  of  several  dentists,  the  patient  is 
wearing,  with  great  satisfaction,  an  upper  denture  made  from  a  dupli- 
cate of  this  impression. 

50 


Fig.    31. 

Four  impressions  of  the  same  moi:th.  A  and  B.  The  direction  of  the  pull  of  the 
buccal  attachments  is  strongly  backward,  in  these  two  impressions  taken  with  the 
mouth  open. 

C.  The  anterior  attachment  has  muscle-trimmed  the  impression  nearer  the  median 
line  and  much  less  deeply. 

D.  The  margin  seems  much  less  deeply  trimmed,  yet  the  impression  is  better 
adapted.     See  opposite  page. 


%--    ^ 


r  r 


A  I'.  C  D 

Fig.   32. 

The   same   Impressions   as    In    Fig.    :!1    with    a    plaster   inipressioii    of   the    same    mouth    on 

the   left. 


51 


THE  AXTEEO-POSTEEIOR  LEXGTH  OF  THE  UPPEE 

IMPEESSIOX. 

The  upper  impression  should  he  of  the  length  desired  in  the 
finished  denture.  This  length  will  Ije  determined  by  the  condition 
of  the  tissues.  If  the  alveolar  ridge  in  the  front  of  the  mouth  is  hard, 
the  denture  should  extend  on  to  the  soft  tissues  immediately  posterior 
to  the  hard  palate.  If  the  alveolar  ridge  in  front  is  soft,  the  denture 
will  need  to  extend  farther  backward,  on  to  the  movable  soft  tissues, 
in  order  that  it  mav  be  stable  in  biting. 

The  nausea  which  frequently  results  from  dentures  has  l:)een  gen- 
erally thought  to  be  caused  ]jy  the  upper  denture  extending  too  far 
backward,  and  efforts  are  made  to  relieve  the  condition  by  shortening 
the  denture. 

Xausea  is  caused  by  imperfect  adaptation  of  the  posterior  margin 
of  the  denture.  If  the  margin  be  adapted  to  lie  in  close  contact  with 
the  tissues  when  relaxed,  the  denture  may  be  carried  back  as  far  as  the 
dentist  desires,  without  causing  nausea.  But  if  the  denture  is  made 
over  a  model  of  the  soft  tissues  in  a  distended  position,  the  posterior 
margin  will  not  lie  in  close  contact  with  those  tissues  when  they  are 
relaxed.  The  soft  tissues  will  then  sustain  an  intermittent,  vibrating 
contact,  which  will  tickle  the  nerve  endino's  and  cause  nausea. 

If  the  tray  be  trimmed  as  suggested  on  page  18,  and  the  posterior 
margin  adapted  as  suggested  on  page  54,  nausea  will  not  result,  however 
long  may  l)e  the  denture.  I  have  seen  many  patients  who  had  previously 
been  unable  to  wear  dentures  because  of  nausea,  and  for  whom  dentures 
had  repeatedly  been  shortened,  who  are  wearing  with  complete  satis- 
faction very  long  dentures  with  the  margins  adapted  to  close  contact 
with  the  tissues  when  relaxed. 


52 


I'i^'.  ■■■.•■;. 

Whistllii;?  iiiovfuicnts  to  carry  the  l)ii'<-!il   ;iUai'liiiiciits  Into   the  aiitorior  iiositioii. 


5.^ 


ADAPTING  THE  UPPER  IMPRESSION  TO  THE  PALATAL 

SOFT  TISSUES. 

Figs.  Nos.  34:  and  35. 

It  is  important  that  the  upper  impression  should  be  adapted  to  the 
soft  tissues  which  overlie  the  posterior  part  of  the  hard  palate  on  either 
side  of  the  median  line  as  shown  in  Fig,  No.  35 A  when  these  tissues  are 
relaxed. 

Impressions  taken  with  the  mouth  open,  yield  models  of  these 
tissues  in  distended  positions.  When  the  mouth  is  closed,  these  tissues 
occupy  very  different  positions,  and  a  denture  made  over  a  model 
of  their  distended  positions  may  fit  them  so  poorly  as  to  cause  the 
nausea  described  on  page  52.  If  the  denture  fits  these  tissues  in  the 
relaxed  position,  it  will  be  stable  at  all  times  and  will  not  cause  nausea, 
no  matter  how  long  it  may  be. 

The  impression  is  adapted  to  the  relaxed  position  of  these  tissues 
by  adding  compound  from  a  stick  over  the  entire  area  occupied  by 
these  tissues,  and  while  it  is  very  soft,  inserting  the  impression  into  the 
mouth,  the  lower  trial  plate  being  in  place,  and  having  the  patient  close 
the  mouth  and  swallow  two  or  three  times.  The  tongue,  is  automatically 
carried  to  the  roof  of  the  mouth  during  swallowing,  and  this  action 
drives  the  softened  compound  into  firm  contact  with  these  tissues  and 
holds  it  there  until  it  cools.  It  may  be  necessary  to  add  compound  in 
this  way  two  or  three  times  before  the  added  compound  blends  smoothly 
with  the  rest  of  the  palatal  surface.  Trim  the  impression  to  the  exact 
length  desired  in  the  finished  plate.  Then  warm  the  posterior  border 
of  the  impression  again  and  have  the  patient  swallow  a  few  times. 

While  the  jaws  are  still  closed  together,  the  patient's  lips  are 
parted,  the  upper  trial  plate  is  seized  with  the  left  thumb  and  forefinger 
in  the  bicuspid  regions,  and  held  firmly  against  the  vault,  the  patient  is 
caused  to  open  the  mouth  and  the  right  forefinger  is  passed  across  the 
heel  of  the  plate  with  gentle  but  firm  pressure  and  the  compound  is 
more  firmly  adapted  against  the  vault  and  posterior  to  the  tuberosities. 

The  finger  pressure  may  carry  the  compound  to  a  point  which  will 
cause  muscle  strain.  Have  the  patient  immediately  close  the  mouth 
and  swallow.  If  the  compound  be  not  too  hard,  this  will  equalize  the 
strain.  If  the  compound  hardens  before  these  steps  are  completed,  it 
should  be  warmed  and  the  process  repeated. 

The  trial  plate  is  now  removed  from  the  mouth  and  the  buccal 
margin  of  each  side  over  the  tuberosities  should  be  warmed  deeply,  by 
the  aid  of  a  small  flame,  without  changing  its  form.  The  trial  plate  is 
now  quickly  replaced  in  the  mouth.  The  patient  is  caused  to  close  the 
jaws  lightly  in  correct  bite,  and  then  to  exert  strong  force  in  biting. 
This  pressure  properly  ^'muscle  trims"  the  posterior  parts  of  the  buccal 
margins  to  the  movements  of  the  muscles  in  this  region.  This  trimming 
is  very  important  and  often  prevents  mutilation  of  the  tissues  due  to 
congestion,  or  a  tendency  to  force  the  plate  forward  in  biting. 

54 


Fig.    34. 

A  stick  of  compound  is  softened  over  the  flames  and  compound  from  it  is  added  to 
the  palatal  surface  of  the  impression  over  the  area  occupied  by  soft  tissues  in  the  mouth 
being  fitted. 


i-'ig.  :-.:>. 

The  areas  within  the  white  lines  In  "A"  are  the  t hcr.rctical  locations  of  tlie  muscular 
tlHHues  overlying  the  hard  palate.  The  area  within  the  white  line  in  "B"  is  that  over 
which  compound  waH  added  In  adaptation  of  this  denture  to  the  relaxed  position  of  these 
muHcles. 


55 


THE  EFFECT  OF  ADAPTATIONS^  TO  THE  PALATE. 

Figs.  jSTos.  36,  37  and  38. 

This  Adaptation  of  the  impression  to  the  soft  tissues  mentioned 
often  effects  an  almost  unbelievable  change  in  form  in  this  part  of  the 
denture.  An  impression  taken  with  the  mouth  open  rounds  downward 
in  this  area,  while  one  which  has  been  adapted  to  the  relaxed  tissues. 
either  runs  out  nearly  horizontal  or  actually  turns  upward. 

Fig.  ]Sro.  37  shows  on  the  left  an  impression  taken  with  the  mouth 
open  and  the  tissues  rounding  downward  in  this  region. 

Fig.  Xo.  37  shows  on  the  right  an  impression  of  the  same  moutli 
with  the  soft  tissues  compressed  in  their  relaxed  position.  ]^ote  that 
the  impression  runs  out  horizontally.  The  diiference  in  thickness  of 
buccal  margins  and  amount  of  compound  may  be  disregarded. 

Fig.  ^o.  38  shows  on  the  right  a  cross  section  of  the  impression  on 
the  left  in  Figure  'No.  37.  ]Srote  the  very  decided  rounding  down  of  the 
soft  tissues  in  the  posterior  portion  of  the  impression. 

A  denture  made  over  a  model  from  this  impression  will  fit  the 
relaxed  soft  tissues  so  poorly  as  to  probably  cause  nausea  by  vibrating 
contact  between  denture  and  tissues. 

Figure  No.  38  shows  on  the  left  a  cross  section  of  the  impression 
shown  on  the  right  in  Figure  No.  37.  oSTote  the  horizontal  formation  in 
the  posterior  portion.  This  impression  is  much  more  stable  in  all  posi- 
tions of  the  mouth.  A  denture  having  this  form  could  be  extended  as 
far  backward  as  the  condition  of  the  ridge  in  the  anterior  section  re- 
quired, without  causing  nausea. 

Similar  differences  of  form  in  other  impressions  can  be  seen  by 
referring  to  Figure  Xo.  36. 

This  completes  the  work  on  the  upper  impression.  It  should  now 
be  stable  in  all  positions  of  the  lips  and  cheeks,  and  should  fit  snugly 
but  not  be  uncomfortably  tight.  That  impression  is  best  which  while 
in  position  in  the  mouth,  can  be  rotated  slightly  from  side  to  side 
without  breaking  suction. 


56 


Fig.   3G. 

A.  Impression  of  open  nnnith.  Poorly  adapted  tray.  Excess  of  compound.  No 
muscle-trimming. 

B.  Impression  of  same  mouth,  open.  Margins  built  up  but  not  trimmed  thin. 
Muscle-trimmed. 

C.  Impression  of  same  mouth,  muscle-trimmed  and  massaged  with  mouth  closed. 
Adapted  to  palatal  soft  tissues.  White  line  outlines  area  over  which  compound  was 
added. 


Fig.   37. 
On  the  left,  an  impression   df  ;i    iiicnith,  open,   with   p;il;it;il   si.rt   tissues  disteinhMl   an 
rounding  down.     On  the  rigid  .-in   iiiipi-cssion  of  tlie  same  iiKuiih   \\iii<-li   lias  Ijeeii  ad.ipti 
to  the  i»alatal  soft  tissues  in    relaxed    pusitidus. 


Fig.   .".8. 
On    tlie   rigid,   a   cpohh   Hpcfion    of   an    inii)ressIon    taken    wltli    tlie    nioutli    open.      Note 
Unw    It    r<>nn<lH    down    In    tlie    posterior    part.      On    tiie    left,    an    impression    of    the    same 
mouth  properly  adapted  to  the  soft  tissues  overlying  tlie  hard  palate. 


57 


ESSEIsTTIALS  OF  COMFOET  IN  A  LOWER  DENTURE. 

The  acme  of  comfort  in  the  average  lower  denture  is  secured  only 
when  the  denture  is  supported  by  pressure  of  its  buccal  and  lingual 
margins  on  the  soft  tissues  at  the  base  or  sides  of  the  ridge,  rather  than 
on  the  top  of  the  ridge.  The  margins  of  the  denture  must  be  adapted  to 
accommodate  these  tissues  in  their  positions  of  extreme  distention,  and 
sufficiently  short  so  that  the  tissues  will  either  not  raise  the  denture  or 
if  they  raise  it,  will  automatically  re-seat  it  when  the  mouth  closes. 

An  impression  which  will  yield  such  a  denture  requires  adaptation 
by  three  distinct  steps : 

1.  The  outer  rim  must  be  "muscle  trimmed"  to  the  buccal  and 
labial  tissues  in  positions  of  maximum  distention.  This  can  be  done 
only  with  the  mouth  open  and  conformed  to  the  ridge  with  the  mouth 
closed. 

2.  The  lingual  rim,  in  the  region  of  the  bicuspids  and  molars,  is 
trimmed  to  the  distended  position  of  the  sublingual  tissues  with  the 
mouth  closed  and  the  patient  swallowing.  The  anterior  portion  of  the 
lingual  rim  is  to  be  trimmed  by  the  patient  sticking  out  the  tongue  or 
licking  the  upper  lip. 

3.  After  the  margins  have  been  trimmed  as  described  under 
ISTos.  1  and  2,  the  ridge  surface  in  contact  with  extremely  hard  or  very 
soft  tissue  must  be  cut  out  considerably  and  then  the  entire  ridge 
portion  of  the  impression  is  softened  and  the  pressure  at  all  points  is 
equalized  under  biting  stress.     This  point  is  most  important. 

The  experienced  operator  will  be  able  to  secure  these  adaptations 
in  not  more  than  three  operations,  but  whether  three  or  ten  are  required, 
they  must  be  effected  if  the  lower  denture  is  to  be  comfortable  and 
efficient. 


58 


FIXISHIXG  THE  LOWER  IMPRESSION. 

If  the  outer  margin  of  the  lower  baseplate  impression  was  cut 
short,  as  directed  on  page  38,  trace  on  additional  compound  from  median 
line  to  heel  on  one  side,  making  it  higher  than  the  finished  rim  wdll  be, 
but  not  thick  from  ridge  to  cheek.  Put  the  trial  plate  into  the  mouth, 
have  the  patient  open  wdde,  and  by  pressure  on  the  bicuspid  region  of 
each  side,  force  it  down  to  place.  Then  have  the  patient  close  the  mouth 
and  perform  the  whistling  and  laughing  movements.  While  the  mouth 
is  closed  and  the  cheeks  are  relaxed,  make  a  quick,  light  massage  over 
the  warm  margin. 

The  movements  of  the  cheeks  will  doubtless  turn  upward  any  excess 
of  compound  that  was  built  on.  This  should  be  trimmed  away,  and 
the  procedtire  repeated  until  no  more  compound  is  turned  upward. 

When  the  margin  is  high  enough  on  one  side  and  is  properly 
trimmed,  repeat  the  process  on  the  other  side  of  the  outer  margin. 

If  the  lingual  margin  of  the  impression  was  cut  short,  trace  on 
compound  in  like  manner,  and  at  the  same  time  warm  the  entire 
balance  of  the  lingual  margin  evenly  and  deeply,  because  the  sublingual 
are  very  weak  but  effective.  Insert  the  trial  plate  into  the  mouth,  the 
upper  being  always  in  place,  and  have  the  patient  close  the  mouth  and 
swallow.  This  will  muscle  trim  the  margins  in  the  bicuspid  and  molar 
region.     Trim  away  excess  and  repeat  till  no  more  excess  is  turned  up. 

Warm  the  lingual  margin  of  the  anterior  region,  hold  the  trial 
plate  down  on  the  ridge  by  pressure  in  the  bicuspid  regions,  and  have 
the  patient  project  the  tongue  or  lick  the  upper  lip.  When  the  tongue 
is  withdrawn,  pass  the  finger  over  the  warmed  margin  and  gently  press 
the  compound  against  the  ridge,  without  changing  its  form. 

With  a  spoon  instrument,  deepen  the  impression  of  any  prominent 
hard  spots  or  very  soft  or  flabby  places  on  the  ridge. 

The  final  step  is  perhaps  most  important  of  all.  If  the  ridge  sttr- 
face  of  the  impression  is  flat,  immerse  it  in  hot  water  to  soften  it  without 
changing  its  form  and  replace  in  the  mouth  and  have  the  patient  bite 
very  lightly  in  right  relations,  and  whistle,  laugh  and  swallow. 

If  the  ridge  is  high,  warm  the  impression  surface  in  contact  with 
top  of  ridge  with  hot  water  from  a  syringe.  This  final  softening  and 
biting  permits  all  inuscl(!  strain  to  be  equalized  and  causes  excess  com- 
pound to  flow  toward  top  of  ridge. 


59 


TAKIjNTG  PAKTIAL  IMPEESSIOiS^S. 

(For  the  benefit  of  dentists  who  desire  to  take  partial  impressions 
the  following  skeleton  of  ]\Ir.  Supplee's  method  is  appended.  Such 
impressions  will  be  found  valuable  in  making  models  for  partial  den- 
tures and  for  extensive  bridgework. 

Lack  of  space  forbids  proper  treatment  of  this  subject.  Those 
desiring  detailed  information  are  respectfully  referred  to  Mr.  Supplee's 
writings. ) 

The  buccal  flange  is  trimmed  away  from  the  tray.  The  impression 
material  is  prepared  as  described  for  full  impressions  and  is  shaped 
to  cover  the  surface  of  the  hard  palate,  the  lingual  surfaces  of  the 
remaining  teeth  and  all  surfaces  of  the  ridge  where  teeth  are  missing. 

Press  the  cup  "home"  and  hold  it  until  the  compound  has  partly 
set.  Remove  the  tray  and  compound  from  the  mouth  in  the  direction 
in  which  the  finished  denture  is  to  be  removed.  Dip  the  surface 
of  the  compound  into  cold  water  to  slightly  chill  it ;  then  quickly  insert 
the  tray  again  in  the  mouth  and  drive  it  "home"  with  pressure. 

Cut  the  margins  of  comjDound  about  adjoining  teeth  to  square 
edges.  Shape  a  roll  of  compound  as  for  a  lower  impression  and  lay  it 
over  the  labial  and  buccal  surfaces  of  the  teeth.  Pull  the  lip  over  it,. 
press  the  compound  in  place,  allow  it  to  cool. 

The  above  steps,  if  properly  followed,  obviate  the  taking  of  an 
impression  of  the  bell-shaped  necks  of  teeth,  which  cannot  be  used  in 
the  finished  denture.  They  make  it  possible  to  produce  a  partial  plate 
which  can  be  inserted  into  the  mouth  without  trimming. 


60 


Fig.  39. 

<  »n   the  left,   a   Siipiih'c  iinper   tray   for   jiartial   innircssioiis. 

(til  tlie  rigrbt.  the  iniiiressidii  of  the  vault  and  the  lingual  surfaces  of  the  teeth,  with 
the  outside  pieces  laid   back  to  show  impressions  of  outer  surfaces  of  teeth. 


fiVKxaJv^sarviJWii.'aMiimzmmmiUMai-Wf-t-i.:. 


Fig.    10. 

•  Ill   (lie   left,   a    Sii|iplec   Iray    for   parliaj    lovscr   iinpicssions. 
On    tin-    rlglit.   a    lower    partial    iin|iressloii    v\ilh    I  he   aulciior    pii 
linprefixloii    (if   labial   siirface.x   of   antcrlors. 


laid    b.'udi    to    show 


61 


poi:n'ts  to  be  kemembered  iit  refitting  upper 
plates  or  in  taking  new  impressions. 

1.  Always  examine  the  mouth,  first  by  feeling  the  tension  of  the 
muscles  with  the  mouth  as  nearly  closed  as  possible,  using  the  index 
finger,  and  you  will  get  an  entirely  different  idea  of  the  existing  con- 
ditions and  the  possible  height  of  rim  than  by  looking  it  over. 

Put  the  finger  in  the  mouth  over  the  tuberosities  and  let  the 
patient  close  to  find  out  the  relation  of  the  lower  jaw  to  the  upper. 
Many  plates  are  thrown  by  the  passing  of  the  two  in  mastication.  Cut 
off  points  of  cusps  which  interfere  with  trituration. 

2.  Don't  push  plate  all  the  way  home.     Let  patient  do  that. 

3.  When  patient  can  tip  plate  with  tongue,  it  is  too  short  in 
the  back, — or  not  imbedded  deep  enough  into  the  soft  tissues. 

4.  When  plate  drops  in  talking,  the  edge  is  not  imbedded  into 
the  soft  tissues  in  the  roof  of  the  mouth  and  back  of  tuberosities. 

5.  When  the  plate  drops  from  mastication,  it  either  rocks  on 
the  hard  palate  or  is  too  low  on  the  sides.  Incidentally,  see  that  there 
are  no  prominent  cusps  catching  on  the  opposite  side  from  which  it 
drops  first. 

6.  When  the  plate  drops  only  when  the  mouth  is  opened  wide,  it 
is  generally  too  high  in  front.  Shorten  it  or  add  material  on  the  inner 
edge ;  it  may  also  extend  back  too  far  on  the  dilating  soft  palate. 

Y.  If  the  patient  gags,  the  plate  is  probably  not  long  enough  or 
is  not  compressing  the  soft  tissues,  so  as  to  eliminate  the  tickling 
caused  by  the  vibration  of  the  soft  tissues  over  the  edge  of  the  plate. 

8.  Build  out  plumpers,  if  required,  in  compound,  when  impres- 
sion is  being  taken. 

9.  After  plate  has  been  worn,  always  cut  out  some  of  the  old 
material  where  you  expect  to  add. 

10.  Don't  build  only  on  the  edge  of  the  rim,  otherwise  you  will 
get  suction  only  by  contact  with  the  cheek,  and  the  plate  will  soon  get 
loose  or  cut  the  cheek.  Add  the  compound  half  between  the  rim  and 
the  bottom  of  the  ridge  so  as  to  compress  the  muscles  at  their  base. 

62 


Fig.   41. 
Very   firm    r-losure   of   ttn"  Jaws   to   trim   the   Impression    margins    to   forward    iiosition    of 

the  massetcr  muscles. 


6.3 


PART     II. 


Selecting  The   Forms  And   Sizes 
In  Anterior  Teeth 


FOEEWORD. 

It  gives  me  great  pleasure  to  be  able  to  introduce  here  tlie  meth- 
ods of  tooth  selection  made  possible  bj  the  researches  of  Dr.  J.  Leon 
Williams,  and  by  the  production  of  Trubyte  Teeth  in  harmony  with 
his  findings.  These  methods  are  so  much  more  scientific  and  certain 
than  those  in  former  use,  and  yield  such  superior  results,  that  T  am 
sure  they  will  replace  all  other  methods  as  soon  as  perception  of  their 
scientific  worth  and  utility  becomes  common. 

The  dentist  who  must  select  teeth  for  a  full  upper  denture,  or 
for  an  upper  partial  denture  extending  across  the  front  of  the  mouth, 
or  for  a  bridge  replacing  the  upper  anterior  teeth,  must  solve  three 
problems,  which  are: 

To  Select  a  Mould  Harmonious  with  the  Face. 

To  Select  Teeth  of  the  Proper  Size. 

To  Select  a  Shade. 

Wlion  only  a  portion  of  the  aiiterior  teeth  are  to  be  selected,  as  in 
the  case  of  some  partial  dentures,  short  bridges,  and  porcelain  crowns, 
the  dentist  must  select  a  mould  of  like  character  with  the  remaining 
natural  teeth,  and  of  tlie  sizes  determined  by  the  mechanical  require- 
ments. 

I  have  briefly  set  forth  Dr.  Williams'  findings  regarding  the  selec- 
tion of  moulds  in  my  own  words  in  the  following  pages. 


67 


THE  ORIGIIsT  OF  FACE  FORMS  AND  TOOTH  FORMS. 

In  tlie  days  when  the  hnman  face  first  assnmed  its  present  pro- 
portions, nature  shaped  three  types  of  face,  the  square,  the  tapering, 
and  the  ovoid  (with  the  big  end  down)  and  made  all  other  forms 
by  blending  these.  They  were  rough  days  and  it  took  rough  men  to 
survive,  even  to  maturity.  Tt  is  natural,  therefore,  that  the  types 
should  have  been  severe  and  strong,  rather  than  what  we  should  call 
pleasing. 

From  those  days  to  these,  nature  has  formed  all  human  faces  in 
these  typal  forms  or  by  blending  these  forms,  usually  with  one  form 
sufficiently  prominent  to  give  its  character  to  the  face  as  a  whole. 
Consequently,  though  we  rarely  have  the  severe  types  of  faces  now, 
faces  may  be  classified  as  modifications  of  the  square,  the  tapering 
or  the  ovoid. 

In  those  early  days  when  nature  was  forming  types,  she  formed 
also  three  types  of  teeth,  and  as  she  seeks  always  beauty  and  harmony, 
the  types  of  teeth  were  harmonious  with  the  types  of  face,  square, 
tapering  and  ovoid.  Since  that  time  she  has  modelled  all  human  teeth 
upon  these  three  forms. 

The  circumstances  which  have  modified  the  forms  of  faces,  seem 
to  have  modified  the  forms  of  teeth  in  like  manner,  so  that  all  teeth 
which  are  not  of  the  severe  typal  forms  may  be  classified  as  modifica- 
tions of  the  square,  the  tapering  or  the  ovoid. 

Dr  Williams  has  conducted  extensive  studies  of  face-forms  and 
tooth-forms,  in  those  museums  which  contain  the  finest  collections  of 
human  skulls.  He  has  demonstrated  that  in  every  race  from  which  we 
have  any  consideral)le  collection  of  skulls,  nature  has  produced  the 
same  typal  forms  of  teeth  and  made  all  other  forms  by  blending  these. 
These  races  are  ancient  and  modern,  savage  and  civilized,  and  from 
every  quarter  of  the  earth. 


kkkkikklkA 


I'iir.    41.      'I'yiial  Idriiis  in   ii])ii('r  centrals,     ("lass  I  at  top. 


I'ijr.    4"J.      Tyjial   tUniis  in   upper  latprnls.     Class  I  at  top. 


II    llllllfi 

kkkkiinui 

kkilkkUikk 


I-'iK.    1.'!.       'I'ypiil   fnrtiis   in    upper  inspids.     Class    I    .'it    top 


HARMONY  BETWEEN  FACIAL  FORMS  AND  TOOTH 

FORMS. 

In  the  davs  before  modifications  of  facial  forms  and  tooth  forms 
became  the  rule,  it  is  possible  that  nature  always  placed  square  teeth 
in  square  faces,  tapering  teeth  in  tapering  faces  and  ovoid  teeth  in  ovoid 
faces.  If  so,  she  secured  harmony,  even  if  the  forms  were  too  severe 
for  our  notions  of  beauty. 

As  modifications  of  typal  forms  in  faces  and  teeth  multiplied, 
nature  seems  to  have  lost  control  of  the  situation,  and  to  have  fre- 
quently allowed  like  modifications'  to  become  separated,  so  that  there 
is  no  longer  any  necessary  relation  between  the  type  of  the  face  and 
the  form  of  the  teeth.  While  there  are  luany  examples  of  harmony, 
there  seem  to  be  even  more  examples  of  disharmony.  Square  teeth  are 
now  often  found  in  ovoid  faces  and  ovoid  teeth  in  square  faces.  The 
extent  of  the  disharmony  and  of  its  effect  is  determined  by  the  character 
of  the  modifications  in  face  and  teeth.  If  both  modifications  tend  toward 
a  common  type,  the  efi'ect  may  not  be  unpleasant.  But  if  they  tend 
toward  different  tjq^es,  the  result  may  not  be  pleasing. 

This  knowledge  of  typal  forms  in  faces  and  teeth,  of  their  modi- 
fications, and  of  the  laws  of  harmony  between  them,  liberates  the  den- 
tist who  is  to  select  all  the  anterior  teeth,  from  any  servitude  to  the 
form  of  teeth  which  the  patient  may  have  exhibited.  His  guidance  is 
to  be  found  in  the  type  of  face,  and  his  task  is  to  select  teeth  to  har- 
monize with  the  face  rather  than  with  any  teeth  which  have  gone 
before. 

When  some  natural  anterior  teeth  remain,  as  in  many  crown  and 
bridge  cases,  the  dentist  will  disregard  the  type  of  face  and  select  a 
mould  to  harmonize  with  the  natural  teeth. 

Dr.'  Williams'  methods  make  such  selection  very  easy  and  rapid, 
but  before  taking  them  up  it  may  be  well  to  devote  a  few  words  to  a 
description  of  the  methods  of  selection  which  have  been  in  force  up  to 
this  time,  but  which  I  believe  will  speedily  become  obsolete. 


70 


fi        ^  -^^^  a 

»                                              - 

If*^ 

^^^^^^^^k.                                                      .  ^^^^^Wj^M^'-                                                                                ,^^^^^^^1 

Fig.  44.     Sandwich  Islanders,  showing  Classes  I,  II  and  III,  In  natural  teeth. 


Fig.  45.     Chinese   Skulls,   showing   Classes   I,    II   and    III,   in   teeth. 


Fig.  4C.     Tu.Huianlaus,  showing   Classes    I,    II   and    III,  In   teeth. 

71 


THE  TEMPERAMENTAL  THEORY  OF  TOOTH  FORMS. 

The  theory  which  has  most  commonly  served  as  a  basis  for  the 
selection  of  teeth  assumes  that  people  can  be  divided  into  four  groups, 
according  to  the  color  of  the  hair,  skin,  and  eyes,  and  the  physical  char- 
acteristics of  size  and  form.  It  assumes  also  that  the  people  of  each 
group  exhibit  a  characteristic  form  of  tooth,  so  that  we  have  a  bilious 
form,  a  sanguine  form,  a  nervous  form,  and  a  lymphatic  form.  The 
temperaments  were  supposed  to  be  blended  together  in  different  propor- 
tions and  the  tooth  forms  to  be  similarly  blended. 

I  have  studied  this  theory  of  temperaments,  but  the  more  I  studied 
the  less  I  knew.  I  believe  this  to  be  the  usual  experience,  and  I  doubt 
if  it  is  taken  seriously  by  many  dentists.  It  has  long  since  been  aban- 
doned in  all  the  other  great  departments  of  medicine. 

The  temperamental  theory  assumes  also  that  there  is  in  each 
human  body  a  governing  principle  which  insures  harmony  of  form  and 
size  among  its  several  parts,  so  that  all  teeth  are  harmonious  in  size 
and  form  with  the  contour  of  the  skull  and  face.  If  this  part  of  the 
theory  were  true,  we  should  all  be  examples  of  symmetry  if  not  of 
beauty,  instead  of  exhibiting  the  rather  heterogeneous  collection  of  eyes, 
ears,  noses,  mouths  and  teeth  which  are  so  common  to-day. 

Dr.  Williams'  studies  have  clearly  established  that  there  are  no 
temperamental  forms  of  teeth  by  showing : 

1st.  That  people  of  every  variation  of  stature  and  color  had  iden- 
tical tooth  forms. 

2nd.  That  people  of  like  stature,  contour  and  color  had  very  un- 
like forms  of  teeth. 

The  following  illustrations  so  establish  these  points  that  we  may 
dismiss  forever  from  our  minds  the  notion  of  temperamental  or  racial 
forms  of  teeth. 

Certain  leading  manufacturers  claim  to  have  produced  porcelain 
teeth  in  moulds  characteristic  of  the  four  great  temperaments.  Un- 
fortunately they  have  differed  so  radically  among  themselves  as  to  have 
produced  entirely  unlike  moulds  for  the  same  temperaments. 

It  is  very  doubtful  whether  the  manufacturers  ever  took  the  temper- 
amental theory  any  more  seriously  than  as  a  means  of  satisfying  certain 
dentists,  obtaining  unpaid-for  advertising,  and  securing  additional  tooth 
orders.  Certain  it  is  that  most  of  the  moulds  of  porcelain  teeth  have 
been  carved  by  copying  natural  teeth,  and  that  largely  without  relation 
to  the  dentist's  needs.  There  has  been  no  system  of  graded  sizes,  so 
that  a  mould  could  be  had  a  little  lar2.er  or  a  little  smaller  than  a  given 
size.  And  many  of  our  finest  efforts  have  been  thwarted  because  suit- 
able teeth  could  not  be  had.  I  believe  Dr.  Williams  is  right  when  he 
says  that  prosthetic  dentistry  has  sunk  to  its  present  neglected  condi- 
tion because  we  have  not  had  proper  teeth  to  work  with. 

72 


Fig.  4".     Ancient  Egyptian  Skulls,  illustrating  the  three  typal  furms  of  teeth. 


Fig.  48.     Skulls  of  modern  Hindoos-   excellent  specimens  of  Classes  I,   II   and    III. 


THE  APPLICATION^  OF  THESE  DISCOVERIES  TO 
PORCELAIN"  TEETH. 

The  discovery  of  the  typal  forms  of  natural  teeth  and  their  modi- 
fications, wonld  be  of  little  value  to  ns  or  our  patients  if  no  porcelain 
teeth  like  them  could  be  had.  Dr.  Williams  knew  this.  He  had  labored 
for  this  discovery  with  the  intention  of  producing  porcelain  teeth, 
which  should  be  harmonious  with  all  forms  of  faces  and  natural  teeth. 
Porcelain  anterior  teeth  shaped  in  accordance  with  his  discoveries  and 
bicuspids  and  molars  shaped  in  accordance  with  Prof.  Dr.  Gysi's  dis- 
coveries,   have   been   produced   under   the   distinctive   name   teubyte 

TEETH. 

Dr.  Williams  calls  the  Square  Type  ''Class  I",  the  Tapering  Tvpe 
"Class  II",  and  the  Ovoid  Type  ''Class  III". 

Dr.  Williams  has  isolated  five  modifications  of  tooth  forms  in 
Class  I ;  four  in  Class  II,  and  four  in  Class  III. 

These  modifications  have  not  been  made  by  copying  natural  teeth. 
That  method  has  proven  a  failure  in  the  hands  of  every  one  who  has 
given  it  serious  trial.  They  have  been  made  by  studying  nature's  work, 
until  her  object  and  her  methods  were  known.  The  defects  which  ap- 
pear in  nearly  all  sets  of  natural  teeth  were  eliminated,  and  the  funda- 
mental principles  of  beauty  in  tooth  form  were  discovered  and  utilized. 
The  laws  of  harmony,  as  exhibited  in  nature's  finest  achievements,  were 
applied  to  the  accomplishment  of  nature's  object,  this  time  in  porcelain. 

A  number  of  practical  advantages  to  us  as  prosthetic  workers  re- 
sult from  this  method.     They  may  be  briefly  summarized  as  follows : 

We  are  taught  how  to  classify  faces  for  selection  of  teeth  for  full 
dentures,  and  how  to  classify  natural  teeth  so  that  we  may  know  what 
type  of  artificial  teeth  we  should  select  in  partial  cases. 

We  may  use  the  drawings  of  facial  outlines  in  this  book  and  quickly 
determine  the  type  and  modification  of  face,  or  the  drawings  of  teeth 
and  determine  the  type  and  modification  of  natural  teeth. 

The  endless  and  seemingly  planless  collection  of  artificial  teeth 
from  which  we  have  selected  in  the  past  gives  way  to  a  comparatively 
few  moulds,  so  arranged  as  to  have  greater  matching  power  than  all  the 
moulds  of  the  past. 

The  availal;)ility  of  the  comparatively  few  moulds  is  much  greater 
than  their  number  would  indicate.  A  given  face  may  lie  on  the  border 
line  between  types,  that  is,  be  a  blending  modification  of,  say  Class  I  and 
Class  II.  It  may  be  that  two  moulds  in  either  class  would  be  suitable. 
We  are  thus  furnished  four  moulds  in,  say  four  sizes  each,  suitable  for 
that  face,  a  thing  unknown  before. 

Each  mould  is  produced  in  several  sizes.  These  sizes  vary  about 
one  millimeter  in  the  length  of  the  labial  surface  of  the  upper  central, 
exclusive  of  collar. 

The  illustration  of  each  mould  and  the  dimensions  of  its  several 
sizes  are  tabulated  to  make  them  immediately  available. 

Identical  moulds  will  be  available  in  vulcanite  teeth,  in  porcelain 
crowns,  and  in  facings  for  bridge  work. 

74 


Fig.  50. 

Nine  skulls  ot  different  ra'-es  and  unlike  size  and  eontour,  all  with  teeth  of  Class  I. 
Tlie  form  and  size  of  the  teeth  bear  no  relation  to  the  form  or  size  of  the  skull. 

NatlonalltleH  from   left  to  right  are: 

.Spanisli,  Sandwleh  Islander,  New  Hebrldean,  German,  .Tavanese,  Ilindno,  I'Mjl  Islander, 
Italian,  Ancient  Egyptian. 


75 


DETEEMII^TI^^G  THE  TYPE  OF  FACE  AND  OF  TEETH. 

If  one  lias  illustrations  of.  the  chief  modifications  of  the  three 
typal  forms  of  faces,  it  is  easy  to  determine  the  dominant  type  in  the 
face,  and  the  character  of  the  modification.  One  has  only  to  compare 
illnstrations  with  the  face,  till  the  illnstration  most  like  the  face  is  found. 
Such  illustrations  will  be  found  on  pages  79,  81  and  83. 

Below  the  illustration  of  each  facial  modification  will  be  found  a 
notation  as  to  which  Trubyte  mould  is  suitable  for  faces  of  that  particu- 
lar form.  The  size  of  the  teeth  will  be  determined  by  mechanical  con- 
ditions which  will  be  described  later. 

Because  this  method  of  selection  is  so  easy  and  rapid,  it  must  not 
be  thought  that  it  is  unscientific.  It  is  in  the  highest  degree  scientific 
and  artistic,  and  is  only  made  easy  because  the  preliminary  work  has 
been  completed  by  Dr.  Williams. 

When  remaining  natural  teeth  are  to  be  matched,  the  outline  illus- 
trations of  tooth  forms  on  pages  85,  87  and  89  should  be  used  to  select 
the  most  suitable  mould  of  porcelain  teeth.  The  size  will  be  determined 
by  the  mechanical  conditions. 

An  illustration  exactly  like  every  face  is  not  necessary  to  success- 
fully determine  the  type  and  modification.  There  are  nearly  as  many 
minute  modifications  as  there  are  faces,  since  a  feature  or  a  line  here 
and  there  will  differ  from  that  found  in  any  other  face.  But  the  pro- 
portions of  length  and  width  are  relatively  constant  in  the  several  chief 
modifications.  And  the  lines  which  bound  the  outline  of  the  face, 
when  seen  full  front,  will  have  one  of  three  general  directions,  parallel, 
converging  downward  or  diverging  downward.  They  are  of  three  gen- 
eral characters,  straight  lines,  flat  curves,  full  curves.  It  is  really  sur- 
prising how  rapidly  and  how  accurately  the  faces  which  present  may 
be  classified,  and  hov\^  close  many  of  them  are  to  the  standard  modifica- 
tions. 


76 


I'ijr.  .',1. 

lOiKlit  sknllis  of  unlike  si/,.'  :iiiil  loiin.  All  cxhil.it  l<'clli  ..1'  Class  111.  The  r.iriii  mid 
mI/,c  <>r  llic  teeth   ))e;ir  no  rehitir.ii    to   llie   roim    or   si/.c>   of   the   sUiill. 

Nittloiialities  from  l<'ft  to  riKlit  :  An  AiistiMlian.  Sandwich  Islander.  Ancient  Efiyptiali, 
Kiillir.   riiinese,   African    Savaj."-.    N<'"    llchridcan.    llimloo. 


11 


MODIFICATIONS  OF  THE  SQUAKE  TYPE  OF  FACE. 

Faces  exliibiting  modifications  of  the  square  type  are  more  mimer- 
ous  than  any  others- — perhaps  as  many  in  number  as  all  the  other  types 
combined. 

Most  faces  of  this  type  exhibit  nearly  parallel  sides,  bounded  by 
straight  lines  or  flat  curves,  with  short  curves  at  the  angles  of  the 
jaw,  and  rather  wide  chins. 

Five  modifications  of  this  type  are  worthy  of  careful  attention. 
Teeth  harmonious  with  these  five  will  be  found  harmonious  with  prac- 
tically all  faces  of  the  square  type. 

The  first  modification  is  one  in  which  the  length  of  the  face  is 
much  greater  than  its  width. 

The  second  modification  is  one  in  which  the  length  of  the  face  is 
but  little  greater  than  its  width. 

The  third  modification  is  one  in  which  the  length  and  width  of  the 
face  are  about  equal. 

The  fourth  modification  is  one  in  which  the  outline  has  been  a  trifle 
softened  by  slightly  lengthening  the  curves  at  the  neck.  It  is  usually 
found  only  in  female  faces,  and  may  be  called  a  feminine  modification. 

The  fifth  modification  is  one  in  which  the  curves  at  the  angles  of  the 
face  have  been  noticeably  lengthened,  and  the  approximal  curves  some- 
what rounded.    This  constitutes  the  oval  face. 

Outlines  illustrating  these  facial  modifications  are  shown  on  the 
opposite  page.  Below  each  has  been  placed  a  notation  as  to  the  mould 
of  Trubyte  teeth  harmonious  with  that  particular  form  of  face. 


78 


Square  face— long. 
Class  I.  Mould  1. 


Square  face— long. 
Class  I,  Mould  1. 


Square  face -medium. 
Class  I,  Mould  2. 


Square  face— medium. 
Class  I,  Mould  2. 


Oval. 


Oval. 


79 


MODIFICATION'S  OF  THE  TAPERi:^rG  TYPE  OF  FACE. 

Faces  of  this  type  are  wider  above  the  eyes  than  below,  and  taper  to 
the  chin  by  straight  lines  or  flat  curves.  The  chins  are  wider  in  some 
faces  than  in  others,  but  they  are  not  the  wide,  square  chins  of  the 
square  type  of  face. 

The  severe  typal  form  of  this  face  expresses  great  force  and  en- 
durance. It  is  most  likely  to  be  found  among  people  who  have  lived 
physically  strenuous  lives,  generally  outside  the  softening  influence  of 
luxury.    It  is  not  pleasing  in  modern  eyes. 

The  crossing  of  races  and  the  influences  of  civilization  have  pro- 
duced modifications  of  this  type  by  blending  with  the  square  or  ovoid 
types,  and  many  of  these  faces  are  pleasing  in  appearance.  Such  faces 
are  perhaps  most  often  found  before  the  period  of  life  when  the  body 
takes  on  excess  tissue  and  its  outlines  change. 

Faces  of  the  tapering  type  do  not  exhibit  the  same  character  of  vari- 
ation between  length  and  width  that  square  faces  do.  There  are,  of 
course,  all  proportions  of  lengths  and  widths,  but  when  faces  of  differ- 
ent proportions  are  compared,  they  are  generally  seen  to  be  different 
modifications  of  the  typal  form,  rather  than  similar  modifications  with 
different  proportions. 

It  is  believed  that  the  illustrations  on  the  opposite  page  are  suffi- 
cient to  enable  the  dentist  to  classify  practically  all  the  facial  modifica- 
tions of  this  type  which  appear. 


80 


Tapering  face — long. 
Class  11,   Moulds. 


Tapering   face — long. 
Class   II,   Moulds. 


'J'apr-ring  faf-e. 
Class   11,   .Moulds. 


Tapering  face. 
Class  II,   .Moulds. 


81 


MODIFICATIOISrS  OF  THE  OVOID  TYPE  OF  FACE. 

The  ovoid  type  of  face  is  distinguislied  by  being  wider  below  the 
eyes  than  above  them.  Faces  of  this  type  are  nearly  always  bounded 
by  lines  exhibiting  compound  curves.  They  frequently  exhibit  wide 
chins,  but  the  differences  in  the  contour  of  the  sides  of  the  face  save 
faces  of  this  type  from  confusion  with  faces  of  the  square  type. 

Ovoid  faces  do  not  exhibit  the  same  kind  of  variation  between 
length  and  width  that  is  found  in  the  square  type.  They  are,  of  course, 
of  all  sizes  and  of  many  proportions,  but  it  will  usually  be  found  that 
faces  of  this  type  which  differ  markedly  in  proportion  of  length  to 
width  are  different  modifications  of  the  typal  form,  rather  than  the  same 
modifications  with  different  proportions. 

Faces  of  this  type  are  more  common  among  people  of  mature  age 
than  among  young  people.  Very  often  people  take  on  flesh  with  the 
passing  of  the  years,  and  the  whole  body  changes  in  outline.  The  face 
fills  out  in  the  lower  part  and  adipose  tissue  may  make  this  part  wider 
than  the  face  above  the  eyes.  People  who  live  in  luxury  and  without 
much  bodily  exercise,  are  more  apt  to  exhibit  this  type  of  face  than 
those  of  abstemious  lives  and  active  physical  habits. 

The  border  line  of  demarcation  between  some  faces  of  this  type 
and  some  of  the  square  type  is  often  very  delicate  and  there  are 
faces  for  which  a  modification  of  either  type  may  be  suitable. 

The  illustration  of  the  faces  on  the  opposite  page  will  assist  in 
classifying  faces  of  this  type. 


82 


Ovoid  face 
Class  III,  Forms 


Ovoid  face 
Class  III,  Forms 


Ovoid  face 
Class  III,  Forms 


Ovoid  face 
Class  HI,  Forms 


83 


MODIFICATIONS  OF  THE  SQUAKE  TYPE  11^  TEETH- 
CLASS  L 

ISTatural  teeth  of  this  type  are  more  common  than  any  others.  The 
upper  centrals  exhibit  parallel  or  nearly  parallel  approximal  sides  for 
1/3  or  1/2  of  the  length  of  the  crown  upward  from  the  incisal  edge. 
The  upper  laterals  and  cuspids  exhibit  similar  formation,  though  not 
always  to  the  same  degree. 

The  necks  of  the  teeth  are  wider  than  in  either  of  the  other  types 
and  join  the  approximal  surfaces  by  rather  short  curves.  All  the  an- 
teriors  have  the  appearance  described  by  the  word  "square." 

The  teeth  of  this  class  exhibit  three  relations  of  length  to  width.  In 
one,  the  length  is  much  greater  than  the  width.  In  another  the  length 
is  but  little  greater  than  the  width.  In  the  third,  the  length  and  width 
are  about  equal.  jSTo  other  type  of  teeth  exliibits  this  peculiar  variation 
of  length  to  width.  These  modifications  are  exhibited  in  Forms  1,  2 
and  3,  Class  I. 

A  very  pleasing  modification  of  this  type  is  found  almost  exclus- 
ively in  female  faces.  It  is  usually  small  in  size,  and  the  square  appear- 
ance has  been  somewhat  softened  by  lengthening  the  curves  a  little. 
This  modification  is  exhibited  in  Form  4,  Class  I. 

The  oval  tooth  is  a  modification  of  the  square  type  and  is  made  by 
lengthening  the  curves  of  the  neck  and  approximal  sides.  This  modi- 
fication is  exhibited  in  Form  5,  Class  I. 

Square  faces  and  square  teeth  are  more  common  than  any  others, 
and  the  five  modifications  here  shown  will  meet  the  requirements  of  a 
great  number  of  cases. 

A  detailed  description  of  each  of  these  forms  appears  in  connec- 
tion with  the  illustrations  and  table  of  sizes  in  the  l)ack  of  the  book. 


84 


CLASS   I  MOULDS 


Form  1.     The  long   square  form. 
The  sizes  are  marked  as  Moulds  IC,  ID,  IE.  IF,  IH. 


Form   2.     The   medium   long    square   form. 
The  sizes  are  marked  as  Moulds  2C,  2D,  2E,  2F,  211. 


Form  :i.     The  short  square  form. 
The  sizes  are  marked  as  Moulds  3C,  3D,  3E,  3F,  3H. 


Form   4.     A   delicate   feminine  modifloation   of  Munhl 
The  sizes  are  marked  as  Moulds  4D,  4E. 


Form   .">.      'I'hc   ov;il    furin. 
The   sizes  are   marked    !is    Moulds  5(',  ijl>,   ijE,   5F 

85 


MODIFICATIONS  OF  THE  TAPEEIN^G  TYPE  OF  TEETH- 
CLASS  II. 


Teeth  of  the  severe  typal  form  are  distinguished  by  nearly 
straight  approximal  surfaces  which  converge  so  rapidly  in  some  cases 
that  they  would  meet  at  the  middle  of  the  root,  and  in  other  cases  at 
the  end  of  the  root.  These  severe  forms  are  rarely  pleasing  and  there  is 
no  necessity  for  their  reproduction  in  porcelain,  since  the  modifications 
exhibit  all  the  typal  characteristics  in  more  pleasing  form. 

Teeth  of  this  type  do  not  exhibit  the  same  kind  of  variations  of 
length  to  width  that  are  seen  in  Class  I.  Teeth  of  this  type  exhibiting 
widely  varying  relations  between  length  and  width  will  usually  be 
found  to  be  different  modifications. 

Form  1  in  this  class  is  the  severe  typal  form  modified  just  enough 
to  rob  it  of  the  severity  and  exhibit  the  beauty  of  the  type.  It  is  a  very 
striking  mould  and  has  commended  itself  to  the  artistic  sense  of  dis- 
criminating workers. 

Form  2  differs  from  Form  1  in  that  the  severity  of  the  typal 
form  is  slightly  more  softened.  This  is  suitable  for  faces  in  which  the 
cheek  lines  are  a  little  fuller  and  not  quite  so  straight. 

Form  3  exhibits  fuller  curves  on  the  distal  surfaces  of  the  upper 
anteriors  and  is  suitable  for  faces  in  which  the  cheek  lines  are  filled  out 
enough  to  present  slightly  convex  curves. 

Form  4  is  probably  the  softest  modification  of  this  type  which  will 
be  required.  It  will  be  found  useful  for  faces  and  teeth  which  are  just 
this  side  the  border  line  between  this  type  and  the  ovoid. 

Each  of  these  moulds  is  offered  in  a  series  of  convenient  sizes. 

When  Dr.  Williams  first  brought  this  type  of  tooth  to  my  atten- 
tion, it  appeared  to  me  as  the  least  beautiful  of  the  typal  forms,  and  I 
thought  it  would  find  less  use  in  prosthesis  than  either  of  the  others. 
I  know  now  that  I  felt  that  way  because  I  had  never  properly  observed 
it  in  natural  teeth.  Since  I  have  learned  to  look  for  it  in  natural 
teeth,  I  find  it  common  in  what  I  might  perhaps  call  the  typical  Ameri- 
can face,  that  is,  the  clean  cut  face  with  straight  cheeks  and  no  superflu- 
ous tissue.  I  find  also  that  in  such  faces  this  form  of  tooth  is  very 
pleasing  and  it  now  seems  to  me  quite  as  fine  as  either  of  the  other  two. 

I  have  seen  these  teeth  in  prosthetic  cases,  and  the  effects  are  very 
pleasing.  There  is  an  appearance  of  clean  cut  vigor  about  them  which 
neither  of  the  other  types  exhibits,  and  dentists  who  wish  to  break 
away  from  the  usual  forms  of  teeth  will  find  the  modifications  of  this 
type  very  useful. 

A  detailed  description  of  each  of  these  forms  appears  in  connec- 
tion with  the  illustrations  and  table  of  sizes  in  the  back  of  the  book. 


CLASS  II  MOULDS 


Form  1. 

A  severe,  nearly  typal  form. 

The  sizes  are  marked  as  Moulds  IL,  IM,  IN,  IP,  IR. 


Form  2. 

The  severity  of  Mould  1  is  here  noticeably  softened. 

The  sizes  form  Moulds  2L,  2M,  2N,  2P,  2R. 


Form  3. 

A  still  softer  modification. 

The  sizes  form  Moulds  3L,  3M,  3N,  3P,  3R. 


Form    1. 
The  softest   modification. 
The  sizes  form  Moulds  4L,  4.VI,  4N,  4P,  4R. 


87 


MODIFICATIONS  IK  THE  OVOID  TYPE  OF  TEETH- 
CLASS  III. 

The  severe  typal  form  of  these  teeth  is,  as  the  word  ovoid  shows, 
distinctly  egg-shaped,  the  big  end  of  the  egg  being  downward.  It  is 
distinguished  by  a  strong  convex  curve  on  the  mesial  approximal  sur- 
face and  a  well  marked  double  curve  high  on  the  distal  surface.  The 
severe  typal  form  would  be  harmonious  only  with  faces  of  very  strongly 
marked  character  and  would  not  be  beautiful  then. 

The  modifications  of  this  type  are,  however,  by  far  the  most 
graceful,  and  in  some  ways  the  most  beautiful  of  natural  teeth.  They 
exhibit  a  delicacy  and  beauty  of  contour  which  neither  of  the  other 
types  can  show,  and  in  faces  for  which  they  are  suitable  cannot  but 
achieve  the  finest  of  results. 

The  modifications  of  this  type  do  not  show  the  same  form  of  vari- 
ation in  length  and  width  as  did  the  square  type.  Different  modifica- 
tions may  be  of  different  length  for  a  given  width,  but  in  any  given 
modification  the  proportions  of  length  and  width  are  relatively  con- 
stant. 

Form  1  is  the  nearest  to  the  typal  form  that  a  modification  can 
be  and  exhibits  the  beautiful  curves  which  are  characteristic  of  this. 
type. 

Form  2  is  a  slightly  softer  modification  and  is  suitable  for  faces, 
not  quite  as  strong  in  type  as  those  requiring  Mould  1. 

Forms  3  and  4  of  this  type  are  still  softer  modifications. 

Each  of  these  forms  is  offered  in  a  series  of  convenient  sizes. 

A  detailed  description  of  each  of  these  forms  appears  in  connection 
with  the  illustrations  and  the  table  of  sizes,  in  the  back  of  the  book. 


CLASS   III   MOULDS 


Form  1. 


A  nearly  tyiial  form  of  imich   strength,  suitable  for  mascnllne  faces. 
The  sizes  are  marked  as  Moulds  lU,  IW,  IX.  lY,  IZ. 


Form    2.      The    typal    form    is    here    modified    and    softened. 

feminine  faces. 
The  sizes  are  marked  as  Moulds  2T 


This    form    is    suitable    for 
2W.   2X,  2Y,   2Z. 


Form 


.     The  typal  form  is  here  more  moditied  than  in  forms  1  and  2. 
The  sizes  are  marked  as  Moulds  3U,  3W,  3X,  3Y,  3Z. 


Form  4.     The   tyjial   form   Is   here  e.vtenslvely   niodilled. 
The  BlzeH  are  marked  as  .Moulds  41',  4W,  4X,  4Y,  4Z. 


89 


SELECTI]^G  ANTEKIOK  TEETH  OF  PKOPER  SIZES. 

Two  methods  of  selecting  artificial  teeth  were  in  vogue  in  my 
early  days  in  practice.  One  was  for  the  dentist  to  go  to  the  depot  and 
there  select  from  among  the  hundreds  of  moulds  the  one  he  thought 
most  suitable.  The  other  was  for  the  dentist  to  send  a  model  and  let 
a  clerk  who  had  never  seen  the  patient,  make  the  selection.  Both  were 
wasteful  of  time  and  often  unsatisfactory  in  result. 

It  seemed  to  me  that  if  I  could  learn  in  advance  just  what  mould 
of  teeth  was  required  by  a  case,  selection  could  be  greatly  facilitated. 
By  measuring  with  a  millimeter  gauge  the  distance  between  the  marks 
which  I  had  been  taught  to  make  on  the  trial  plates  for  the  high  lip 
line  and  the  low  lip  line,  and  adding  one  or  two  other  marks,  it  became 
very  easy  to  tell  just  how  long  a  central  was  needed,  how  wide  a  set 
of  anteriors,  and  how  wide  a  full  set  of  fourteen. 

When  this  method  was  published  under  the  title  of  The  Twentieth 
Century  Method  of  Selecting  teeth,  accompanied  by  tables  of  tooth  di- 
mensions in  millimeters,  it  was  necessary  only  to  scan  the  tables  until 
the  mould  most  nearly  like  the  requirements  was  found.  The  order 
could  then  be  sent  by  mould  number.  It  was  quicker,  easier,  and  more 
satisfactory  than  the  old  method. 

Experience  has  shown  no  reason  for  changing  this  method  for  se- 
lecting sizes.  It  has  found  its  way  into  all  corners  of  the  world,  has 
become  standard  practice  in  many  offices  and  is  taught  in  several  col- 
leges. It  has  placed  selection  in  the  hands  of  the  dentist,  who  is  most 
competent  to  select  well ;  has  made  it  evident  that  teeth  for  full  dentures 
must  be  selected  from  the  trial  plates  and  not  from  the  model;  has 
shortened  the  time  required  for  selecting  moulds,  has  insured  the  re- 
ceipt by  the  dentist  of  just  the  teeth  he  had  in  mind  for  the  case;  and 
has  resulted  in  the  selection  of  more  satisfactory  teeth  in  most  cases. 

The  length  of  upper  central  should  be  marked  first,  then  the  length 
of  the  lower  central,  then  the  width  of  the  six  upper  anteriors.  The 
width  of  the  upper  central  is  determined  by  the  form  which  was  se- 
lected by  means  of  Dr.  Williams'  drawings. 

The  patient  is  asked  to  raise  the  upper  lip  in  smiling,  and  the  lo- 
cation of  its  edge  is  marked  on  the  trial  plate.  If  the  necks  of  the  upper 
centrals  are  located  on  this  line,  the  gums  will  not  be  exposed  in  smiling. 

The  chances  are  better  than  3  in  5  that  this  is  the  right  location  for 
the  necks  of  the  upper  centrals,  because  out  of  some  thousands  of  people 
whom  I  counted  smiling,  3  in  every  5  raised  the  lip  to  the  level  of 
the  necks  of  the  upper  central.  Even  if  this  would  make  the  teeth 
a  little  long,  it  is  more  artistic  to  have  them  so  than  to  expose  pink 
rubber  in  smiling  and  a  greater  expanse  of  it  in  laughing. 

If  the  lower  lip  is  depressed  by  the  action  of  the  depressor  muscles 
and  the  location  of  its  edge  is  marked  in  the  same  way,  it  will  indicate 
the  point  to  which  the  lower  centrals  must  extend  to  prevent  exposure 
of  the  lower  gum  in  smiling. 

If  the  orifice  of  the  mouth  is  well  proportioned  to  the  face,  the 
distal  angles  of  the  upper  cuspids  may  with  advantage  come  close  to 
the  angles  of  the  orifice.     To  locate  these  angles,  an  instrument  is  in- 

90 


Fig.  52. 

The  upjier  li|»  was  raised   by   ttio  elevator  muscles  and  Is   held   by   the   tiiiger  merely  for 

purposes  of  Illustration. 


91 


SELECTING  ANTEKIOK  TEETH  OF  PROPEK  SIZES— 

Continued. 

troduced  between  the  lips,  in  the  median  line,  and  moved  to  one  angle 
and  then  the  other  and  a  mark  on  the  trial  plate  at  the  location  of  each, 
after  the  manner  shown  in  Figure  JSTo.  53.  If  the  orifice  is  nndnly 
large  or  small  for  the  other  features,  the  distance  between  the  marks 
may  be  shortened  or  lengthened.  But  it  should  be  remembered  that  the 
teeth  are  closer  to  the  orifice  than  to  the  other  features,  and  that  it  is 
better,  on  the  whole,  for  them  to  be  a  little  large  or  small  for  the  other 
features  than  noticeably  large  or  small  for  the  orifice. 

One  other  dimension  in  anterior  teeth  is  important  at  least  in  cases 
where  the  absorption  of  gum  tissue  is  so  slight  as  to  leave  little  room 
between  the  upper  and  lower  ridges.  It  is  the  dimension  of  that  part 
of  the  teeth  intended  to  sit  below  the  level  of  the  upper  ridge,  or  above 
the  level  of  the  lower  ridge.  It  is  the  dimension  of  the  greatest  com- 
bined bite  and  shut  available  in  the  case.  A  short  study  of  an  artificial 
anterior  tooth  will  make  plain  the  meaning  and  importance  of  this 
dimension. 

Figure  'No.  54  represents  a  vertical  section  through  an  upper  an- 
terior tooth.  It  will  be  seen  that  the  lingual  surface  has  three  divisions, 
the  bite,  the  shut,  and  the  ridge-lap.  Of  these,  the  shut  and  ridge-lap 
are  intended  to  sit  below  the  level  of  the  ridge  in  those  cases  where  the 
denture  must  be  so  thin  in  front  that  the  teeth  be  close  to  the  ridge.  In 
cases  where  the  absorption  of  the  anterior  plate  of  the  upper  alveolus 
is  complete,  the  teeth  will  usually  be  placed  a  little  way  in  advance  of 
the  ridge,  and  the  length  of  the  combined  bite  and  shut  is  therefore 
not  so  important.  But  in  those  close  bite  cases,  where  little  room  is 
available  at  best,  attention  to  this  detail  will  enable  the  dentist  to  select 
teeth  of  a  size  which  will  not  need  to  be  ground. 

Before  I  adopted  Mr.  Supplee's  method  of  making  the  impression 
into  a  trial  plate,  it  was  easy  to  thrust  a  pin  through  the  wax  of  the 
trial  plate  on  a  level  with  the  surface  of  the  ridge.  But  the  presence 
of  the  impression  tray  in  the  trial  plate  renders  this  method  imprac- 
ticable. It  is,  however,  easy  to  measure,  on  the  palatal  side  of  the  im- 
pression, the  distance  from  the  top  of  the  rim  to  the  deepest  part  of 
the  impression,  and  transfer  this  measurement  to  the  labial  surface  of 
the  trial  plate,  where  it  answers  every  purpose  accomplished  by  the 
pin  hole. 

The  area  to  be  filled  with  anterior  teeth  is  now  well  defined  on 
the  trial  plates,  and  it  is  necessary  only  to  determine  the  distances  in 
millimeters,  and  to  have  at  hand  the  dimensions  of  the  required  teeth. 
The  distance  from  the  high  line  to  the  incisal  edge  of  the  trial  plate  is 
the  length  of  the  labial  surface  of  the  upper  central  incisor.  The  dis- 
tance from  the  low  line  to  a  point  a  millimeter  above  the  incisal  edge 
of  the  lower  trial  plate  is  the  length  of  the  labial  surface  of  the  lower 
central  incisor.  The  distance  from  the  mark  at  one  corner  of  the  ori- 
fice around  the  trial  plate  to  the  other  similar  mark,  is  the  width  of 
the  upper  anteriors,  when  set  up.     If  the  bite  is  close,  the  distance  from 

92 


l-i;r.   .'..;. 

It   is   hi-tUT  to   iiisf-rt   the   iMstniipicnt    in    the   iri<Mli;iii    line   ;iiiil   move   it   to   the  ailKlcs.     The 
pjitlcnt    is    less    likely    to   ilniw    tlic    Ii|i    t);i<-li    ami    uivc   a    false   location. 


93 


SELECTII^G  A^TTERIOK  TEETH  OF  PROPER  SIZES 

— Continued. 

the  surface  of  the  upper  ridge  to  the  incisal  edge  of  the  trial  plate  is 
the  required  combined  bite  and  shut  of  the  upper  central. 

If  now,  reference  is  had  to  table  in  which  the  dimensions  of  the 
several  sizes  of  the  required  type  of  tooth  are  listed  in  millimeters,  the 
size  most  suitable  can  readily  be  selected.  It  can  then  be  ordered  by 
mould  number. 

Millimeter  measurements  of  Dentsply,  Solila,  Twentieth  Cen- 
tury and  Trubyte  teeth  are  given  as  tables  in  the  back  of  this  book. 
With  all  the  variations  possible  to  the  human  mouth,  one  must  not 
expect  to  always  find  a  mould  exactly  right  in  every  particular.  But 
with  surprising  frequency  a  mould  will  be  found  which  will  closely 
approximate  the  required  dimensions.  And  selection  by  this  method  is 
likely  to  be  more  satisfactory  than  by  the  haphazard  methods  of  the 
past. 

Dr.  Williams'  classification  of  faces  and  teeth  and  standardization 
of  sizes  greatly  facilitate  satisfactory  selection.  Many  faces  exhibit 
modifications  which  lie  between  two  types  of  teeth,  as  between  the 
square  and  ovoid  types.  For  such  faces  a  modification  of  the  square 
type  and  a  modification  of  the  ovoid  type  may  be  equally  suitable.  If, 
in  such  a  case,  the  required  dimensions  cannot  be  found  in  the  mould 
of  the  square  class,  it  is  possible  that  they  may  be  obtained  in  an 
equally  suitable  mould  in  the  ovoid  class. 

DETERMINING  THE  WIDTH  OF  THE  FULL  SET. 

When  the  trial  plates  have  been  taken  from  the  mouth,  it  can  be 
determined  how  far  back  on  each  side  the  teeth  should  extend.  A  mark 
can  then  be  made  to  locate  the  distal  side  of  each  second  molar.  This 
location  cannot  be  made  in  the  mouth,  or  from  any  measurements  taken 
in  the  mouth,  but  is  determined  wholly  by  the  dentist's  judgment. 

By  measuring  around  the  trial  plate  from  one  of  the  marks  to  the 
other,  the  width  of  the  full  fourteen,  in  millimeters,  is  determined. 
This  measurement  affords  an  example  of  the  importance  of  selecting 
teeth  from  the  trial  plate  rather  than  from  the  model.  The  width  of 
the  full  set,  when  in  place  on  the  model,  is  from  2  to  4  or  5  millimeters 
greater  than  the  width  of  the  set  when  flat  on  the  wax.  It  is  important 
therefore  that  sizes  should  be  selected  from  tables  having  the  dimensions 
of  the  anteriors  and  full  sets  when  set  up. 

It  is  not  uncommon  for  a  mouth  to  be  so  ill-proportioned  as  to 
require  wide  anteriors  and  narrow  posteriors.  If  full  sets  do  not  come 
carded  to  meet  such  requirements,  the  dentist  may  make  up  his  own 
sets  ordering  anteriors  and  posteriors  separately. 

Trubyte  posteriors  are  made  in  four  mesio-distal  widths,  28  m.m., 
30  m.m.,  32  m.m.,  and  34  m.m.  The  dentist  may  order  any  of  these 
for  use  with  any  anteriors,  but  if  disproportionate  sizes  are  ordered,  it 
will  be  necessary  to  grind  for  adjustment  where  the  posteriors  and  an- 
teriors join. 

94 


COLLAR-/ 


COMBINED 

BITE 

AND 

SHUT 


-.,    RIDGE 
7    LAP 


SHUT<, 


BITE 


Fig  54. 
Section  through  an  upper  central  showing  the  divisions  of  the  lingual  surface 


Fig.  55. 
Trial  plates  markcrl  for  measuring. 


95 


Fig.  56. 


Fig.  57. 
Measuring  bite   horizontally  to  get  combined   width   of  six  anteriors   and  full   set  of  14. 


96 


selecti:n^g  teeth  for  partial  cases,  bridges  and 

CROWXS. 


The  most  satisfactorv  and  economical  method  of  selecting  any  form 
of  teeth  for  cases  where  less  than  the  fnll  denture  is  to  be  restored  is 
to  have  at  hand  a  Mould  Guide  of  the  make  of  the  teeth  to  be  used,  and 
to  fit  sample  teeth  from  that  guide  onto  the  case.  By  this  means,  both 
dentist  and  patient  can  see  just  what  the  effect  is  to  be.  The  order 
for  the  teeth  can  be  made  out  by  mould  and  shade  number,  and  the 
results  will  be  as  desired.  Or  regular  stock  teeth  can  be  kept  on  hand 
and  tried  in  this  way. 

This  method  is  far  more  available  with  Trubyte  teeth  than  with 
any  others,  because  identical  moulds  of  vulcanite  teeth,  platinum  pin 
facings  and  porcelain  crowns  will  be  produced.  It  therefore  requires 
the  dentist  to  keep  fewer  teeth  on  hand.  For  the  selection  of  a  porcelain 
crown,  the  vulcanite  teeth  may  be  tried  in  place.  The  labial  surface  of 
the  porcelain  crown  will  be  like  that  of  the  vulcanite  tooth,  and  the 
mould  will  have  the  same  number  in  crowns. 

Dentists  who  do  not  wish  to  purchase  a  Mould  Guide  or  stock  teeth 
to  use  as  such,  may  apply  the  Twentieth  Century  Method  of  Selecting 
Teeth,  and  procure  the  dimensions  of  the  required  teeth  in  millimeters, 
by  using  calipers  to  measure  the  space  for  a  single  tooth,  or  by  making 
a  partial  trial  plate  and  measuring  around  the  curves.  Selections  can 
be  made  from  the  tables  in  the  back  of  this  book. 


SELECTING  LOWER  TEETH. 

When  full  upper  and  lower  sets  are  selected  at  one  time,  no  meas- 
urements for  the  lowers  need  be  taken.  If  upper  teeth  are  not  being 
selected,  the  sizes  of  the  required  lowers  should  be  marked  on  the  lower 
trial  plate,  the  dimensions  o])tained  in  millimeters,  and  selections  made 
from  the  tables  in  this  book. 

For  full  dentures,  the  bicuspids  and  molars  should  be  of  the  com- 
bined mesio-distal  width  necessary  to  extend  the  full  set  back  to  the 
locations  marked  for  the  distal  sides  of  the  second  molars. 

For  full  cases  Trubyte  Molar  Blocks  will  be  found  superior  to 
plain  teeth.  They  are  made  in  the  same  moulds  and  shades  as  the  plain 
vulcanite  teeth.  They  are  described  in  connection  with  Trubyte  bicus- 
pids and  molars. 

For  partial  cases,  the  plain  teetli  or  Molar  Blocks  should  be  selected 
from  a  Trubyte  Mould  Guide.  Much  better  selection  results  from  try- 
ing in  the  sample  tootli  thnii  is  y)ossible  by  any  system  of  measurement. 

97 


PART    III. 


Colors  In  Natural  And  Artificial 

Teeth 


FOEEWOED. 

Color  plays  as  important  a  part  in  determining  the  beauty  of  arti- 
ficial teeth  and  their  suitability  for  any  given  case  as  does  form  or  size. 
If  the  color  and  shade  selected  are  harmonious  with  that  of  the  general 
complexion  in  edentulous  cases,  or  the  other  teeth  in  partial  cases, 
minor  discrepancies  in  form  or  size  are  seen  only  on  close  examina- 
tion. But  if  the  color  or  shade  is  noticeably  wrong,  the  falseness  of 
the  restoration  is  at  once  detected.  And  no  perfection  of  form  or  size 
can  make  up  for  the  visible  defect  in  color. 

When  Dr.  Williams  entered  upon  the  work  of  incorporating  into 
porcelain  teeth  all  the  perfections  of  natural  teeth,  it  quickly  became 
evident  that  the  number  of  subjects  concerning  which  knowledge  must 
be  crystallized  and  systematized  was  too  great  for  one  man  to  cover 
the  whole  field.  The  subject  of  color  was  assigned  to  me  for  investiga- 
tion. I  have  given  the  subject  extensive  study  and  have  at  least  some 
of  the  results  in  concrete  form.  They  have  been  applied  to  Trubyte 
teeth,  and  I  shall  try  to  make  plain  in  what  ways  they  enable  the 
prosthetist  to  improve  the  appearance  of  his  work. 


101 


THE  COLOK  SCHEME  IN  NATURAL  TEETH. 

Until  one  has  studied  the  colors  in  natural  teeth,  he  cannot  realize 
how  complicated,  how  delicate  and  how  beautiful  is  the  color  scheme 
bj  which  nature  adorns  a  reallj  fine  set  of  teeth. 

When  the  lips  are  parted  in  smiling,  so  that  parts  of  both  sets  are 
seen,  the  teeth  form  a  band  of  color  which  shades  away  in  all  directions 
from  the  point  of  highest  light  in  the  incisal  halves  of  the  upper  cen- 
trals, to  softer  colors  and  shadows  in  the  upper  cuspids,  bicuspids  and 
molars,  and  darker  shades  and  softer  shadows  in  the  lower  anteriors. 
Nature  thus  introduces  into  the  face  a  spot  of  very  high  light  and 
blends  it  away  so  softly  that  no  sense  of  disharmony  is  created. 

Only  when  the  eye  has  time  to  penetrate  the  shadows  between  the 
teeth,  do  the  forms  or  sizes  of  individual  teeth  become  visible.  If  the 
color  of  the  teeth  is  harmonious  with  that  of  the  patient's  complexion, 
the  general  appearance  will  be  pleasing,  even  if  the  teeth  are  not  exactly 
harmonious  in  form  and  size  with  the  face.  Dentists  who  are  con- 
fronted with  the  necessity  of  selecting  teeth  too  large  for  the  features, 
other  than  the  orifice,  may  do  much  to  conceal  the  size,  by  selecting  a 
suitable  color  and  shade. 

Natural  teeth  exhibit  every  color  of  the  rainbow.  The  primary 
colors,  red,  blue  and  yellow  are  found  in  every  human  tooth.  At  least 
one  of  the  secondary  colors,  orange,  green  or  violet  is  found  in  every 
tooth,  generally  with  an  excess  of  some  primary  color  which  gives  to  the 
tooth  its  recognized  color  as  a  blue,  a  yellow  or  a  pink.  Gray  teeth  oc- 
cur when  there  is  no  excess  of  primary  color. 

The  coloring  in  natural  teeth  is  ingeniously  designed  to  enhance 
the  value  of  the  mechanical  effects.  The  anteriors  round  outward  and 
backward  from  the  median  line.  This  is  in  harmony  with  the  round- 
ing away  of  the  features,  but  it  is  rendered  much  more  pleasing  to  the 
eye  by  the  subtle  change  in  the  colors  of  the  laterals  and  cuspids.  The 
light  rounds  away  with  the  form. 

Nature's  skill  as  a  craftsman  is  exliibited  in  the  effects  which  she 
achieves  by  changing  the  depth  and  distribution  of  color  in  the  lower 
anteriors,  as  compared  with  the  uppers.  This  effect  greatly  enhances 
the  overhanging  effect  of  the  upper  anteriors,  softens  the  contrast  be- 
tween the  lower  lip  and  the  teeth,  and  when  aided  by  the  red  reflection 
from  the  lip,  seems  to  merge  tlie  necks  of  the  lower  anteriors  into  a  band 
of  soft  color  which  serves  as  a  base  for  the  whole  color  scheme  of  the 
anteriors.  One  can  hardly  appreciate  the  delicacy  and  beauty  of  this 
effect  until  he  studies  a  set  in  which  the  shading  is  strong  enough  to 
be  noticeable,  and  sees  how  nature  has  used  the  deep,  soft  colors  of  the 
lower  incisors  and  the  soft  shadows  that  fall  between  them,  as  a  founda- 
tion for  the  lighter  colors  in  the  upper  anteriors.  The  most  beautiful 
sets  are  those  in  which  the  color  scheme  is  so  delicately  worked  out  that 
its  elements  can  be  recognized  only  by  careful  study. 

102 


HOW  COLOR  IJs^  XATURAL  TEETH  WAS  STUDIED. 

While  much  has  been  written  and  more  has  been  said  about  the 
colors  and  shadings  in  natural  teeth,  as  compared  with  those  in  porce- 
lain teeth,  nothing  written  could  be  found  which  was  of  value  in  ar- 
riving at  the  definite,  workable  conclusions  that  are  necessary  when  the 
fruits  of  an  investigation  are  to  be  incorporated  into  articles  of  manu- 
facture. It  therefore  became  necessary  to  undertake  this  study  from 
the  beginning. 

The  services  of  experts  in  colors  were  obtained,  and  a  number  of 
persons  with  beautifully  colored  and  shaded  natural  teeth  were  selected. 
Laboratory  conditions  in  cleanliness  of  teeth,  purity  of  light,  absence  of 
shadows  and  reflections,  and  other  such  conditions  as  fine  color  work 
requires,  were  established. 

The  method  of  measuring  color  values  now  approved  by  the  finest 
color  analysts  was  adopted.  This  system  accepts  as  a  unit  of  color,  the 
smallest  amount  of  red,  yellow  or  blue  that  can  be  perceived  by  the  eye 
of  an  intelligent  person  not  specially  trained  in  color  work.  This  depth 
of  color  is  marked  witli  the  figure  "1"  and  is  multiplied  to  measure 
stronger  colors  and  divided  to  measure  fainter  colors.  The  experts 
who  assisted  in  this  work,  or  more  accurately  whom  I  assisted,  could 
perceive  and  place  1/100  of  a  unit  in  any  color. 

By  means  of  special  appliances  devised  for  the  work,  the  cervical 
half  of  each  tooth  was  isolated  for  color  measurement,  and  the  incisal 
half  was  later  isolated  in  like  manner.  The  anteriors,  the  bicuspids  and 
the  first  molars  were  measured  in  this  way.  The  work  is  very  difficult; 
in  fact,  it  is  by  far  the  most  difficult  ever  attempted  by  these  experts, 
on  account  of  the  character  of  the  tooth  substance,  and  the  delicacy, 
complexity  and  soft  blending  of  the  shades.  The  dif^culties  may  be 
partly  appreciated  when  it  is  stated  that  after  a  steady  look  of  5  seconds 
the  vision  is  no  longer  true  for  color  and  that  two  hours  of  continuous 
work  exhausts  a  strong  person  for  a  day. 

The  amount  of  color  seen  in  the  tooth  as  a  whole  was  first  de- 
termined. This  color  was  then  broken  up  into  its  component  parts  and 
the  proportions  of  the  several  parts  determined.  The  work  was  checked 
by  making  a  sample  color  like  the  portion  of  the  tooth  which  it  repre- 
sented. 

I  spent  a  great  deal  of  time  and  about  two  thousand  dollars  of 
The  Dentists'  Supply  Company's  money  in  studying  and  reproducing 
tooth  colors,  and  am  able  to  offer  what  is,  I  believe,  the  first  exact 
knowledge  concerning  the  colors  of  natural  teeth  and  certainly  the  first 
application  of  that  knowledge  to  the  manufacture  of  porcelain  teeth. 
Xo  claim  is  made  for  originality  and  the  work  is  far  from  being  as  com- 
plete as  I  should  like  to  see  it.  But  until  some  one  has  not  less  than 
two  years  to  study  tlie  subject,  and  a  large  sum  of  money  foi"  the;  em- 
|)Ioyment  of  experts,  little  more  can  be  acconi})liKhed. 


COLOR  ANALYSIS 


Miss  D.  A. 


Age  19 

Ht.  5.6" 

Wt.  119  lbs. 


Color  Developed 


Black    Orange 


UPPERS 

U.  R.  Central 

' '       Ivateral 

' '       Cuspid 

"       1st  bicuspid 
"       2nd       " 
"       1st  molar. . . 

I/.   Central 

' '       Lateral 

"       Cuspid 

"        1st  bicuspid 
"       2nd       " 
"       1st  molar. . . 


U. 


LOWERS 
Iv.  R.  Central 

' '      Lateral 

' '      Cuspid  . . . . . 

"      1st  bicuspid, 
L.  Iv-  Central .    . . . 

' '      Lateral 

' '      Cuspid 

"       1st  bicuspid. 


Eves 
Hair 
Skin 


I  Cervical  \ 
\  Incisal      / 


f  Cervical 
\  Incisal 
f  Cervical 
1  Incisal 
j  Cervical 
\  Incisal 
f  Cervical 
1  Incisal 
Cervical 
Incisal 
Cervical   / 
Incisal      ^ 
Cervical 
Incisal 
I  Cervical 
i  Incisal 
I  Cervical 
\  Incisal 
f  Cervical  1 
\  Incisal     1 
\  Cervical  1 
I  Incisal      ) 
Cervical  / 
Incisal      \ 


Cervical 

Incisal 

Cervical 

Incisal 

Cervical 

Incisal 

Cervical 

Incisal 

Cervical 

Incisal 

Cervical 

Incisal 

Cervical 

Incisal 

Cervical 

Incisal 


17.5 
Dead 
4.1 


1.1 

1.1 

1.85 

1  85 

1.85 

1.9 

2.0 

2.0 

2.0 

2.4 

1.1 

1.1 

1.85 

1  85 

1.95 

2.0 

2.0 
2.0 

2.4 


1.0 
1.0 
2.4 
2.3 
2.6 
2.3 

2.0 

1.0 

1.25 
2.4 
2  3 
2.4 
2.2 

2.0 


43.0 
Blac 
3.0 

1.4 

1.35 

2.9 

2,7 
3  3 
3.1 
2.7 
2.6 

2.3 

3.7 

1  5 
1.4 
2.9 
2.5 
3.2 
3.1 

2,7 
2.3 
3.6 


2.5 
2.4 
3.4 
2.9 
3.3 
2.7 

2.5 


2.6 
2.5 


16.0 
k 

.88 


.20 
.34 

1.3 

1.7 

1.75 

1  85 

1.6 

1.7 

1.6 

2.3 

.20 
.38 
1.3 
1.6 
1.75 
1.8 

1  6 
1.6 
2,3 


.74 
.76 

1.6 

1.8 

1.5 

1.55 

1.5 

.74 
.95 

1.6 

1.8 

1.45 

1.5 

1.5 


16.0 


.20 
.34 

1.3 

1.7 

1.75 

1.85 

1.6 

1.7 

1.6 

2.3 

.20 
.38 
1  3 
1.6 
1.75 
1.8 

1.6 
1.6 
2.3 


.74 
.76 

1.6 

1.8 

1.5 

1.55 

1.5 

.74 
.95 
1.6 

1.8 

1.45 

1,5 

1  5 


1,5 
2.12 


25.5  yel. 
1,1  red 


.90 
.76 
.55 
.15 
.10 
.05 
.40 
.30 

.40 

.10 

.90 

.72 
.55 
.25 
.20 
.20 

.40 
.40 
.10 


.26 
.24 
.80 
.50 
1.1 
.75 

.50 

.26 
.30 
.80 
.50 
.95 
.70 

.50 


.3 

.25 
1.05 

.85 
1.45 
1.2 

.7 

.6 

.3 

1.3 

.4 

.3 
1.05 

.65 
1.25 
1,1 


.3 
1.2 


1.5 

1.4 

1.0 

.6 

.7 
.4 


1.5 

1  15 

1.0 

.6 

.7 
.4 


104 


(For  convenience  of  those  not  accustoniert  to  studying  such  charts,  I  have  put  the 
colors  in  the  right  hand  teeth  ou  the  reader's  right  hand,  and  not  in  the  reverse  form 
common  to  dental  charts.) 


I      1 

1 



1 

^ibxJGs^^. 

\:/^]gI:  _:: 

||||||:[:^'YI 

¥-l^-J/l4lllllllllllll 

;::::: 

c 

If         '    '  ' 

1   1 

r  "!!! 

t : 

t  ::::: 

i;  JL — Lj_i  1 

T  -X-- 

it--m 

-^  -i  .  YE 

iLOW       t" 

; ; 

li  ;  1 

j_ 

--— r-p 

- 

— k_  ^  -^. 

0,6 ^ 

!    ,      i  i 

1                    : 

(- 

jhi              _            

0.4    -  -  -  -  . 

;  ■ ;     1 : : !  1 : 1 

'  '     l^i  l"             "-"  - 

t-rT' 

*NGE-  ^-:-L_J 

^=r?rtr-nTTrr- 

Depths  of  colors  in  the  necks  of  the  upper 
anteriors. 


Depths    of   colors   in    the   incisal   halves    of 
the  upper  anteriors. 


DIAGRAMMATIC  REPRESENTATION  OF  THE  DEPTHS  OF  COLOR 
TABULATED  ON  PAGE  104. 

The  different  depths  of  color  in  different  parts  of  a  tooth  and  in  different 
teeth  can  be  diagrammatically  shown  in  charts  like  those  here  reproduced. 

The  horizontal  base  line  of  the  charts  represents  0  in  color.  Each  of  the 
parallel  horizontal  chart  lines  represents  a  depth  of  1/10  of  a  unit,  upward 
from  0.  The  line  locating  the  gray  in  the  teeth  is  drawn  solid.  That  represent- 
ing the  orange  is  drawn  in  dashes  and  that  representing  the  yellow,  in  dots. 
This  set  of  teeth  showed  no  other  colors. 

This  person's  hair  is  dead  black,  the  eyes  are  brown,  and  the  skin  showed 
a  good  deal  of  red. 

The  charts  show  that  the  necks  of  the  upper  centrals  and  laterals  in  this 
set  exhibit  less  gray  than  the  cutting  edges,  but  more  orange  and  yellow.  The 
cuspids  exhibit  practically  the  same  amount  of  gray  and  orange  throughout 
the  teeth,  but  the  necks  show  more  yellow  than  the  cutting  edges.  This  free 
yellow  gives  these  cuspids  their  character. 

The  necks  of  one  lower  central  and  both  lower  laterals  in  this  set,  exhibit 
less  gray  than  the  cutting  edges,  but  the  necks  of  the  lower  laterals  exhibit 
more  orange  and  yellow.  The  lower  cuspids  exhibit  practically  an  even  depth 
of  gray  throughout,  but  much  more  orange  and  yellow  in  the  necks.  There  is 
a  good  deal  more  orange  in  the  lower  cuspids  than  in  the  upper  cuspids. 

A_  study  of  these  charts  shows  how  the  color  deepens  and  softens  in  all 
directions  from  the  incisal  halves  of  the  upper  centrals,  and  how  utterly 
impossible  it  is  for  artificial  teeth  all  of  a  shade  to  meet  the  artistic  require- 
ments of  prosthesis. 


l»<-I'thM   of  lolors   In    tlic   iiciks   of  tlic   iowei 
anteriors. 


iS=yyb:=!:===E;; 


Dcplhs    of 


II    the    iiicis.'il 
■r  interiors. 


halves   of 


105 


COLOR  ANALYSIS 


Miss  K.  B.  G. 


Age  31 

Ht.  5.4^2" 

Wt.  113  lbs. 


Red 


Color  Developed 


UPPERS 
U.  R.  Central 

' '      Ivateral 

"      Cuspid 

"      1st  bicuspid. 

"      2nd       " 

"      1st  molar    . . 
U.  Iv.   Central 

' '       I^ateral 

"      Cuspid 

"      1st  bicuspid 

"      2nd       " 

IvOWERS 
Iv.  R.  Central 

' '      I^ateral 

' '      Cuspid 

"      1st  bicuspid. 

"      2nd       " 

"       1st  molar. .  . 
Li.  L,.  Central 

' '      Lateral 

' '      Cuspid 

"      1st  bicuspid. 

"      2nd       " 

"      1st  molar.  . . 


Eyes 
Hair 
Skin 


f  Cervical 

\  Incisal 

j  Cervical 

(  Incisal 

/  Cervical 

\  Incisal 


Cervical 

Incisal 

Cervical 

Incisal 

Cervical 

Incisal 


Cervical 

Incisal 

Cervical 

Incisal 

Cervical 


\   Incisal 


Cervical 

Incisal 

Cervical 

Incisal 

Cervical 

Incisal 


16.5 

17.0 

4.1 


2.0 
1.8 
2.0 
1.8 
2.7 
3.6 

2.7 
2.4 

3.5 

2.0 
1.8 
1.9 
1.8 

3.7 
3.6 

2.7 
2.5 


2.9 
1.9 
3.0 
1.9 
3.6 
2.1 

3.2 
3.3 

3.4 

2.7 
2.0 
3.0 
1.9 
3.6 
2.1 

3.1 
3.3 

3.5 


17.5 

23.0 

2.4 


1.8 
1.9 
2.5 
1.9 
4.2 
4.5 

2.4 
2.1 

3.3 

1.8 
1.9 

2.5 
2.2 
4.6 
3.8 

2.5 
2.2 


3.0 
1.7 
3.0 
1.7 
3.6 
2.0 

3.1 
3.3 

3.3 

2.9 
1.8 
3.0 
1.7 
3.6 
2.0 

3.1 
3.3 
3.3 


13.5 
14.0 
.70 


1.9 

1.8 

1.55 

2.4 

2.2 

2*5 

1.7 
1.6  . 

2.9 

1.9 

1.25 
1.55 
1.5 

2.3 
2.5 

1.7 
1.6 


2.2 
1^7 
2.2 
1.7 
2.4 
1.9 

2.2 
2.3 

2.6 

1.9 
1.8 
2.2 
1.7 
2.4 
1.9 

2.2 
2.3 
2.5 


13.5 
14.0 
.70 


1.8 
1.8 

1.55 
1  8 
2.2 
2.5 

1.7 
1.6 

2.9 

1.8 
1.25 
1.55 
1.5 

2.3 
2.5 

1.7 
1.6 


2.2 
1.7 
2.2 
1.7 
2.4 
1.9 

2.2 
2.3 

2.6 

1.9 
1.8 
2.2 
1.7 
2.4 
1.9 

2.2 
2.3 
2.5 


3.0  or. 
3.0  " 
1.7    " 


.1  vio. 

.45  or. 
.1  gr. 
.5  or. 
1.1     " 


.4    " 

.1  vio. 

.55  or. 

.35  " 

.3     " 

1.4     " 

1.1     " 


1.2 
.1 

.9 
1.0 

.7 


1.2 
.1 

.9 
1.0 


1 . 0  yel. 
6.0  " 
1 . 7  red 


.Ired 
.1  yel. 
.5     " 
.5  blue 
1.5  yel. 
.9     " 

.3  red 
.3     " 

.2     " 

.1  " 
.  1  yel. 
.6  " 
.4  " 
.9  " 
.2     " 

.2  red 
.3     " 


.1  yel. 
.2  red 


.2  yel. 
.2  red 

.2     " 

.1     " 


106 


(For  convenience  of  those  not  accustomed  to  studying  such  charts,  I  have  put  the 
colors  in  the  right  hand  teeth  on  the  reader's  right  hand,  and  not  in  the  reverse  form 
common  to  dental  charts.! 


Depths  of  colors  in  the  necks  of  the  upper       Depths    of   colors   in    the   incisal    halves    of 
anteriors.  the  upper  anterlors. 

DIAGRAMMATIC  REPRESENTATION  OF  THE  DEPTHS  OF  COLOR 
TABULATED  ON  PAGE  106. 

The  patient's  hair  and  eyes  are  of  very  nearly  the  same  depth  of  brown, 
except  that  the  eyes  have  more  of  a  yellow  tinge.  The  excess  of  red  in  the 
skin  renders  it  very  light. 

The  teeth  differ  from  those  charted  on  the  foregoing  page  in  that  the  pro- 
portion of  red  is  greater,  sometimes  enough  so  that  it  remains  as  a  free  color 
and  gives  the  teeth  a  pink  shade. 

The  upper  right  central  is  of  even  depth  of  gray  throughout.  The  color  in 
the  neck  is  much  softened  by  the  presence  of  violet  and  red,  while  the  incisal 
half  exhibits  free  yellow.  The  upper  left  central  exhibits  much  deeper  gray 
in  the  neck  than  in  the  tip.  It  shows  violet  and  red  in  the  neck  but  only  gray 
in  the  cutting  edge. 

The  upper  right  lateral  exhibits  deeper  gray  in  the  tip  than  in  the  neck, 
but  the  neck  exhibits  orange  which  is  lacking  in  the  tip,  and  the  yellow  is  much 
deeper  in  the  neck  than  in  the  tip.  The  upper  left  lateral  is  of  even  gray 
throughout,  and  shows  orange  and  j^ellow  in  the  neck.    The  tip  is  of  pure  gray. 

The  upper  right  cuspid  is  of  deeper  gray  in  the  tip  than  in  the  neck,  but 
the  neck  exhibits  orange  which  is  lacking  in  the  tip,  and  the  yellow  is  much 
deeper  in  the  neck  than  in  the  tip.  The  upper  left  cuspid  shows  slightly  mors 
gray  in  the  tip  than  in  the  neck,  but  the  neck  shows  deep  orange  and  con- 
siderable yellow. 

The  necks  of  the  lower  anteriors  show  much  more  gray  than  do  the  tips, 
and  this  depth  of  color  is  increased  by  the  presence  of  considerable  orange. 
The  color  in  the  incisal  halves  of  the  lower  centrals  and  laterals  is  deeper  than 
in  the  incisal  halves  of  the  upper  centrals  and  laterals. 


'■'■   '■'■'■'-    lot-  ' 

■b 

nrio 

mm 

"] 
dL 

i  .  '  o  w 

De[)thH  of  colorH  in   tlie  necks  of  the  lower        iKpths    of    colors    in    llic    iiicis.il    halves    of 
•interiors.  'Ill'   lower  iiiitcriors. 


107 


(For  convenience  of  those  not  accustomed  to  studying  such  charts,  I  have  put  the 
colors  in  the  right  hand  teeth  on  the  reader's  right  hand,  and  not  in  the  reverse  form 
common  to   dental  charts.) 


!S 

5     -^-1     - 

/     -,-- 

V  - 

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'        1 

\- 

-\     it 

t 

j  - 

.2__3£_- 

.--t 

^^^^ 

. 

,  , 

i.  ..  ..  .1 

vif'ifiw  ■^■^■S.. 

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._^„,„_ 

1             1 

L ..J 

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o5  "  " 

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t;;= 

—±------^ 

Depths  of  colors  in  the  necks  of  the  upper 
anteriors. 


\s:t  _, 

01 


iiiii 


RANGE- 


YEtltOW 


IJfc 


Depths   of  colors  in   the  incisal  halves   of 
the  upper  anteriors. 


DIAGRAMMATIC  REPRESENTATION  OF  THE  DEPTHS  OF  COLOR 
IN  A  SET  OF  TEETH  NOT  TABULATED. 

The  anteriors  of  this  set  of  teeth  exhibit  only  gray,  orange  and  yellow. 
The  depth  of  gray  is  so  nearly  uniform  in  the  necks  of  the  upper  anteriors, 
that  it  varies  only  1/10  of  a  unit  from  central  to  cuspid.  The  orange  is  un- 
usually deep  in  the  necks  of  the  centrals  and  still  deeper  in  the  laterals  and 
cuspids.  The  yellow  is  much  deeper  in  the  neck  of  one  lateral  than  in  the 
other,  and  is  strong  in  the  cuspids. 

The  gray  and  yellow  are  practically  as  deep  in  the  incisal  halves  of  the 
upper  incisors  as  in  the  necks,  but  the  orange  is  only  half  as  deep.  There  is 
only  half  as  much  yellow  in  the  incisal  halves  of  the  upper  cuspids  as  in  the 
necks,  and  about  2/3  as  much  orange. 

The  lower  incisors  exhibit  practically  a  uniform  depth  of  gray  in  necks 
and  incisal  halves,  but  there  is  less  orange  and  a  good  deal  less  yellow  in  the 
incisal  halves.  The  lower  cuspids  are  of  nearly  uniform  color  throughout, 
and  exhibit  deeper  color  than  any  of  the  other  anterior  teeth. 
,  The  above  colors  combine  to  produce  a  set  of  natural  anteriors  of  a  grayish 
yellow  cast,  with  enough  red  in  the  color  to  give  brilliance.  The  lower  an- 
teriors are  darker  than  the  uppers  and  serve  as  a  base  for  the  color  scheme. 
The  incisal  halves  of  the  upper  centrals  form  the  spot  of  high  light,  and  the 
color  deepens  beautifully  into  the  necks  of  the  upper  centrals.  The  color 
deepens  gradually  and  effectively  through  the  upper  laterals  and  cuspids. 


Depths  of  colors  in  the  necks  of  the  lower 
anteriors. 


Depths    of   colors    in    the   incisal   halves   of 
the  lower  anteriors. 


108 


HOW  THE  COLORS  ARE  PLACED  IN  XATURAL  TEETH. 

Xatiire  exhibits  in  the  coloring  of  the  teeth  the  infinite  variety  of 
her  other  works,  is^o  two  sets  exhibit  exactly  the  same  depth  or  location 
of  color,  and  no  two  teeth  in  any  of  the  sets  studied  are  exactly  alike. 
Indeed,  the  depth  of  color  in  the  teeth  on  one  side  of  the  mouth  is  often 
different  from  that  on  the  other. 

Those  sets  of  natural  teeth  in  which  the  colors  blend  so  softly  that 
the  separate  parts  of  the  color  schemes  are  seen  only  when  studied,  are 
most  beautiful.  Others  are  more  striking,  but  after  a  time  they  seem 
less  pleasing,  because  of  the  strong  contrasts. 

In  order  that  Trubyte  teeth  might  exliibit  the  colorings  of  the 
£nest  sets  of  natural  teeth,  an  average  of  the  colorings  in  several  beauti- 
ful sets  has  been  made  and  incorporated  into  the  porcelain. 

In  finely  colored  sets  of  natural  teeth,  the  incisal  halves  of  the  up- 
per centrals,  taken  together,  form  the  spot  of  highest  light  in  the  face, 
except  the  white  of  the  eyes,  which  is  so  sheltered  as  not  to  form  a 
striking  point.  The  shade  usually  deepens  as  one  goes  toward  the 
necks  of  the  teeth,  though  this  is  not  always  the  case.  Centrals  which 
are  lighter  in  the  incisal  halves  carry  out  better  the  color  scheme  of  the 
teeth  as  a  whole,  than  those  with  darker  cutting  edges.  The  two  centrals 
exhibit  minute  differences  of  color,  but  the  color  effect  as  a  whole  is 
very  much  alike  in  the  two  teeth. 

The  color  in  the  upper  laterals  is  usually  deeper  than  that  in  the 
centrals  and  it  is  more  evenly  distributed  throughout  the  area  of  the 
tooth.  The  incisal  half  of  the  lateral  is  therefore  of  deeper  shade  than 
the  incisal  half  of  the  central.  The  two  upper  laterals  are  rarely  ex- 
actly alike. 

The  color  in  the  upper  cuspids  is  nearly  always  deeper  in  shade 
than  in  either  the  centrals  or  the  laterals.  The  neck  is  sometimes  much 
deeper  than  the  incisal  half,  sometimes  but  little  deeper,  and  sometimes 
the  tooth  is  nearly  of  uniform  color  throughout.  The  finest  cuspids 
are  undoubtedly  those  in  which  the  color  is  deeper  in  the  cervical  half. 

The  color  deepens  through  the  bicuspids  and  molars,  in  some  cases 
more  rapidly  than  in  others.  Those  sets  are  most  beautiful  in  which 
it  deepens  softly.  The  sets  in  which  it  deepens  very  rapidly  appear  too 
deeply  colored  at  the  cervical  margins. 

The  color  in  the  incisal  halves  of  the  lower  incisors  is  deeper  than 
in  the  incisal  halves  of  the  upper  anteriors.  The  color  in  the  necks  is 
deeper  than  in  the  incisal  edges.  The  lower  cuspids  usually  present 
deeper  colors  than  the  incisors  in  both  the  cervical  and  incisal  halves. 

Xature  seems  to  appreciate  that  the  color  scheme  of  the  teeth  does 
not  usually  contemplate  the  exhibition  of  the  lower  bicuspids  and 
molars  and  they  present  no  noticeable  differences  from  similar  upper 
teeth. 

109 


THE  VAGAKIES  OF  COLOR  IK  KATUEAL  TEETH. 

These  illustrations  show,  in  pictorial  form,  the  colors  present  in 
one  set  of  natural  anterior  teeth ;  their  locations  in  the  several  teeth  and 
their  relative  densities.  The  color  was  measured  for  each  half  of  each 
tooth. 

This  is  not  one  of  the  sets  previously  illustrated. 


GRAY 


THE   VAGARIES   OF   COLOR   IX    XATURAL   TEETH— Cont. 

The  secondary  colors,  shown  on  the  opposite  page,  are  nearly  always 
accompanied  by  an  excess  of  one  or  more  primary  colors  and  this  excess 
of  color  gives  the  teeth  their  character.  The  three  primary  colors 
were  in  evidence  in  this  set  as  follows : 


RED 


111 


COLOES  AND  SHADES  11^  OEDII^ARY  ARTIFICIAL  TEETH. 

Artificial  teeth,  as  regularly  furnished,  have  heretofore  been  of 
one  shade  throughout  the  full  upper  and  lower  sets.  This  has  made  it 
impossible  for  dentists  to  select  a  shade  which  was  satisfactory  for  the 
high  lights  in  the  upper  centrals  and  the  deeper  colors  in  the  other  teeth. 

Individual  dentists  have  made  efforts  to  change  this  condition  by 
grinding  or  staining  teeth,  or  by  selecting  teeth  from  different  shades 
and  assembling  them  into  one  set.  In  the  hands  of  a  few  dentists  the 
staining  method  has  yielded  beautiful  results,  but  the  time  and  skill  re- 
quired for  each  case  were  such  as  rendered  a  high  fee  necessary.  The 
method  of  selecting  teeth  of  different  shades  is  rarely  satisfactory 
because  the  different  shades  in  any  shade  guide  were  not  intended  for 
such  selection,  and  teeth  assembled  from  such  shades  show  variations 
unlike  those  in  fine  natural  teeth.  Moreover,  the  method  requires  the  ex- 
penditure of  much  time  and  access  to  a  large  stock  of  teeth. 

ISTaturally  shaded  artificial  teeth  have  never  been  available  before 
for  three  reasons,  which  come  directly  home  to  us  as  dentists.  The  first 
is  that  we  have  never  offered  any  intelligent  plan  for  the  coloring  of 
teeth.  We  have  left  it  to  manufacturers  who  are  not  dentists,  and  who 
cannot  see  our  work  as  we  see  it,  to  solve  the  difficult  problems  as  to 
what  true  tooth  colors  are  and  how  they  are  placed. 

The  second  reason  is  that  we  have  not  known  when  teeth  were 
properly  shaded.  I  persuaded  certain  manufacturers  to  shade  very 
beautifully  100  sets  of  vulcanite  teeth  and  send  them  out  in  the  regular 
course  of  business,  without  any  comment.  Some  of  them  were  accepted 
without  remark.  Others  were  returned  with  the  comment  that  if  the 
manufacturer  could  not  match  teeth  better  than  that,  the  dentists  would 
trade  elsewhere.  ]^ot  a  single  favorable  comment  was  received.  Our 
attitude  as  a  profession  has  been  that  we  were  entitled  to  ask  for  a  thing 
and  then  to  leave  the  manufacturer  to  find  out  what  we  need,  how  to 
make  it  and  to  educate  us  to  an  appreciation  of  it  when  made.  Such 
an  attitude  is  not  worthy  of  us,  and  we  are  entitled  to  make  little  com- 
plaint if  the  solutions  of  the  past  have  not  been  to  our  liking. 

The  third  reason  is  hardly  less  strong  than  the  other  two.  Most 
of  us  have  been  unwilling  to  pay  for  the  production  of  superior  products. 
We  know  so  little  of  our  own  costs  of  production,  that  we  do  not  under- 
stand why  fine  articles  cannot  be  produced  for  the  same  price  as  ordi- 
nary articles.  It  is  economically  impossible.  The  superior  quality 
results  from  the  application  of  a  greater  amount  of  intelligence  and 
skill.  That  demands  more  time,  and  more  wages  and  slower  produc- 
tion. 

112 


COLOKS  AXD  SHADES  IX  TRUBYTE  TEETH. 

Tnibyte  teeth  are  "shaded"  in  the  sets,  on  the  basis  of  extensive 
data  similar  to  that  described  in  the  foregoing  pages.  They  are  made 
in  all  of  the  25  shades  on  the  Twentieth  Century  Shade  Guide. 

The  upper  central  is  always  of  the  shade  on  the  Guide.  The  shad- 
ing of  the  set  is  accomplished  by  varying  the  depth  of  this  color.  Xo 
other  colors  are  added  to  get  the  effects. 

The  color  in  the  upper  laterals  is  more  evenly  distributed  through- 
out the  tooth,  as  was  described  in  connection  with  natural  laterals. 
The  upper  cuspids  are  more  deeply  shaded  in  both  cervical  and  incisal 
halves  than  either  the  centrals  or  laterals.  The  color  in  the  bicuspids 
and  molars  deepens  softly. 

The  shade  in  the  incisal  halves  of  the  lower  anteriors  is  deeper 
than  that  in  the  incisal  halves  of  the  upper  anteriors,  while  the  color  in 
the  necks  is  deeper  still.  This  permits  the  artistic  effect  of  the  over- 
hanging upper  teeth  to  be  achieved,  and  builds  up  the  color  scheme  as 
has  been  described.  I  believe  this  to  be  the  first  time  that  this  beauti- 
ful color  scheme  has  ever  been  applied  to  porcelain  teeth  produced  in 
commercial  quantities  and  available  to  all  dentists. 

All  teeth  may  be  ordered  from  the  number  on  the  Shade  Guide. 
The  only  dift'erence  from  the  teeth  heretofore  furnished  will  be  that 
teeth,  crowns  and  facings  for  laterals,  cuspids,  bicuspids  and  molars,  will 
be  properly  shaded. 

Great  artistic  and  economic  advantages  result  from  this  shading : 

It  is  unnecessary  to  stain  teeth,  save  in  rare  cases.  The  colors  in 
the  tooth  are  finer  than  can  be  gotten  by  staining.  The  teeth  are  avail- 
able without  any  loss  of  time  and  at  surprisingly  low  cost  considering 
the  additional  cost  of  production. 

It  is  unnecessary  to  select  teeth  of  different  shades  and  assemble 
them  into  a  set.  Teeth  thus  assembled  cannot  exhibit  the  beauty  of 
coloring  found  in  these  teeth.  Xo  time  need  now  be  lost  in  such  selec- 
tion. 

Dentures  made  with  properly  shaded  teeth  are  artistically  so  su- 
perior to  those  made  with  teeth  all  of  one  shade,  that  no  comparison 
can  well  be  made. 

The  beauty  of  a  fine  arrangement  is  greatly  increased. 

We  are  enabled  to  offer  to  appreciative  patients,  the  finest  product 
of  our  time  for  all  prosthetic  work  requiring  porcelain.  Such  work 
demands  a  fee  commensurate  with  the  results.  And  many  of  us  who 
have  hesitated  to  ask  remunerative  fees  for  prosthetic  work  because  we 
were  not  satisfied  witli  the  appearance  of  our  own  work,  may  now  have 
the  confidence  to  undertake  such  work  with  pleasure  and  with  the  cour- 
age to  dfrnniifl  adequate  reward. 

113 


SUGGESTIOXS  FOE  SELECTIXG  COLOES  AXD  SHADES. 

"While  the  teeth  exhibit  much  less  color  than  the  skin,  the  iris  of 
the  eves,  and  the  hair  in  most  cases,  they  exhibit  much  deeper  colors 
than  appear  when  contrasted  with  the  skin.  And  few  dentists  have  the 
courage  to  select  artificial  teeth  with  sufficient  depth  of  color. 

Useful  information  about  the  colors  in  teeth  may  be  gained  by 
forming  dark  paper  into  a  roll  about  an  inch  in  diameter  and  ten  inches 
long,  shaping  one  end  to  fit  about  the  eye  to  exclude  the  side  lights, 
and  covering  the  other  end  of  the  tube  with  dark  paper  in  the  center 
of  which  is  a  hole  about  ys  inch  in  diameter. 

Seat  the  patient  in  good  but  not  brilliant  liglit  and  in  such  man- 
ner that  neither  the  natural  teeth  nor  the  shade  teeth  exhibit  shadows 
or  reflections.  Reflections  from  brightly  colored  walls  sometimes 
change  the  color  seen.  Apply  the  paper  tube  to  the  eye  and  isolate  the 
tooth  to  be  matched  from  all  others  and  from  the  lip.  This  permits  one 
to  perceive  the  color  more  truly.  When  the  color  is  determined,  select 
the  sample  tooth  of  the  proper  color  by  trying  in  the  usual  manner, 
beginning  w^ith  the  darkest.  Beware  of  light  colors  and  shades.  Use 
them  only  when  certain  that  nothing  else  will  appear  so  well  in  the 
mouth.  The  basic  color  in  all  teeth  is  gray.  It  is  most  commonly 
affected  liy  yellow,  so  that  the  color  is  really  a  yellow  built  on  a  gray 
base.  It  is  sometimes  affected  toward  the  blue,  and  in  rare  instances 
toward  red  or  green. 

Dentists  who  distrust  their  own  skill  in  selecting  shades  will  be 
greatly  aided  by  the  natural  shading  in  Trubyte  teeth.  This  helps  to 
hide  any  slight  error  in  shade  and  makes  the  laterals  and  cuspids 
appear  more  natural  than  is  possible  with  teeth  all  of  one  shade.  This 
will  be  found  especially  helpful  in  the  selection  of  facings  and  porcelain 
crowns. 

When  teeth  for  full  dentures  are  to  be  selected,  the  dentist  should 
select  a  color  and  shade  that  harmonize  with  the  skin  of  the  lip.  All 
reference  to  the  hair  and  eyes  can  be  omitted,  for  they  show  such  ex- 
treme variations  of  color,  that  no  rules  can  be  laid  down  for  establish- 
ing harmony  with  all  three. 

If  the  skin  is  examined  through  the  paper  tube,  it  will  often  be 
found  to  exhibit  a  surprising  amount  of  red.  In  such  cases,  teeth  with  a 
good  deal  of  life  in  the  color,  as  in  Twentieth  Century  Shades  7  and  9, 
will  of^ten  be  found  suitable.  When  the  color  in  the  skin  is  deeper,  the 
color  in  the  teeth  should  be  deeper. 

A  shade  guide  of  the  same  make  as  the  teeth  to  be  used  should  al- 
ways be  employed  in  selecting  shades.  Shade  Guides  may  now  be  had 
on  such  liberal  terms  that  a  dentist  should  always  have  on  hand  at  least 
two  of  his  favorite  make,  in  order  that  in  very  particular  cases  the 
sample  tooth  may  be  sent  with  the  order  for  more  exact  matching. 

114 


A  TAI5LE  OF  THE  C'OLOlfS  IX  THE  TWENTIETH  CENTURY 

SHADE  GUIDE. 

Sliade  Xo.    1.      Lightest  shade  in  use.     So  coloi-inj^'. 

Shade  Xo.   2.      Trace  of  purple. 

Shade  Xo.   •').      Trace  of  l)hie.      Trace  of  yellow.      Liiihtest   blue. 

Shade  Xo.   4.      Trace  of  yellow.      Lightest  yellow. 

Shade  Xo.  5.  "^rrifle  of  gray  and  trace  of  yellow.  Point  saiiu! 
as  Xo.  4.     X'^eck  darker. 

Shade  Xo.  0.  Same  as  Xd.  4,  wirh  ;i  linlc  gray  in  tin;  rip.  Xeck 
not  so  bright  a  yellow  as  Xo.  5.    Lightest  gray. 

Shade  Xo.  T.  Light  yellow.  Darker  than  X"o.  5,  wMtli  color 
decidedly  stronger  in  neck. 

Shade  X'o.  S.  Light  yellow.  Tij)  darker  than  Xo.  .".  oi'  Xo.  7. 
X'eck  lighter  than  X'o.  7,  and  makes  tooth  look  a  straw  coloi'.  More 
uniform  than  X^o.  7.     Yellow  is  the  only  color  present. 

Shade  X'o.  1).  A  little  yellow,  a  little  gray,  a  little  j)ink.  Light 
brown  yellow  neck.     Tip  pink  gray,  follows  X^o.   IL 

Shade  Xo.    10.      Gray.     Lighter  than  Xo.  ••>.     Darker  than  Xo.  0. 

Shade  Xo.  11.  Uniform  gray  throughout.  X'eck  grayish  yel- 
low slightly  darker  than  10,  which  it  follows. 

Shade  Xo.   12.      Grayish  blue.      Follows   Xo.   •'>   in    the   hhies. 

Shade  Xo.   13.     Grayish  blue.      Follows  Xo.  !). 

Shade  X'o.  14.  Yellowish  gra\'.  Cirav  vellow  neck.  Follows 
Xo.  1.3. 

Shade  XTo.  15.  Pinkish  gray.  Decidedly  darker  and  shows  more 
pink  than  X^o.  1».  The  other  grays  are  bluish  grays.  This  follows 
X'o.  14. 

Shade  X'o.   10.     Yellow.      Follows   X'o.    8. 

Shade   X'o.    17.      Greenish  yellow.     Green  tip  and  yellow  neck. 

Sliade  X'o.    IS,      Dark  yellowish  gray.     Follows  Xo.   14. 

Shade  X'o.   li>.     Dark  gi-eenish  yellow.     Follows  X'o.  17. 

Shade  Xo.   20.      Brownish  yellow.      Follows  Xo.    16. 

Shade  Xo,  21.  Dark  brown  yellow.  Follows  Xo.  20,  which  it 
is  like,  only  darker. 

Shade  X^.   22.      Dark  gray.     Follows  Xo.  18. 

Shade  Xo,   23.      Darkest   brown  yellow.      Follows  Xo.    21. 

Shade  X"o.   24.      Dark  grayish   brown.      P^dlows  Xo.   22. 

Shade  X'o.    25.      Dark  yellowish  brown.      Follows  Xo.  23. 

(Light  shades,  1-2. 
^'ellows,  4-5-7-8-10-1 7-1 1>-20-21-23-25. 
firays,  0-10-11-0-13-14-15  lS-2-24. 
lilues,  3-12. 

115 


EITAMEL  MAEKIi^GS  11^  :^rATUEAL  ANB  PORCELAIN" 

TEETH. 

The  labial  surfaces  of  the  finest  specimens  of  natural  teeth  are  not 
smooth,  but  are  marked  by  a  series  of  fine,  horizontal  striations,  which 
vary  in  character  in  different  parts  of  each  tooth. 

These  markings  break  up  and  diffuse  the  light,  so  that  portions  of 
it  from  all  surfaces  are  directed  away  from  the  eye,  while  portions  of 
it  from  all  surfaces  reach  the  eye.  The  effect  is  to  soften  both  the  bril- 
liant lights  and  the  shadows.  In  natural  teeth  in  which  the  labial 
surfaces  have  been  worn  smooth,  the  light  is  not  so  diffused.  The  teeth 
have  a  hard  look,  and  it  is  concerning  such  teeth  that  criticism  is  some- 
times passed  that  they  must  be  false. 

Artificial  teeth  in  the  past  have  exhibited  smooth  labial  surfaces, 
sometimes  broken  by  strong  developmental  grooves,  or  horizontal 
grooves,  probably  intended  to  represent  defective  calcification.  Such 
grooves,  however,  were  not  of  the  character  required  to  diffuse  the  light 
and  give  to  the  teeth  a  natural  appearance. 

Artificial  teeth  have  looked  false  partly  because  the  surfaces  have 
been  too  glassy  and  because  they  have  reflected  strong  high  lights  sur- 
rounded by  deep  shadows.  Such  teeth  cannot  be  made  natural  in  ap- 
pearance. 

In  connection  with  the  studies  in  color,  I  took  up  the  study  of 
the  markings  in  anterior  teeth.  With  the  co-operation  of  Dr.  Williams 
and  Prof.  Grysi,  the  most  satisfactory  forms  of  markings  for  reproduc- 
tion in  porcelain  teeth  were  determined.  The  methods  in  use  for  the 
production  of  the  ordinary  porcelain  teeth  could  not  produce  teeth  with 
the  desired  markings.  The  manufacturer  undertook  the  invention  of 
methods  which  should  produce  the  required  results.  After  two  years 
of  experimentation,  the  methods  were  perfected  and  teeth  with  proper 
markings  produced.  Teeth  with  these  markings  are  superior  to  teeth 
without  them  for  the  following  reasons : 

The  markings  are  anatomically  correct  and  produce  the  proper  dif- 
fusion of  light. 

The  diffusion  of  light  greatly  softens  the  appearance  of  the  teeth, 
so  that  teeth  with  the  markings  appear  more  like  fine  natural  teeth  than 
teeth  of  identical  size,  color  and  porcelain  without  the  markings. 

The  high  lights  on  each  tooth  are  greatly  softened  and  the  glassy 
reflection  is  taken  away. 

The  shadows  are  softened  so  that  the  teeth  do  not  present  such 
strong  contrasts  of  light  and  shade. 

The  shading  in  the  teeth  is  greatly  enhanced  in  naturalness  and 
value. 

The  color  scheme  in  each  set  of  anterior  teeth  and  in  the  two  sets 
can  be  very  much  better  reproduced  by  the  dentist  in  crowns,  facings 
and  Aadcanite  teeth. 

116 


PART    IV. 

Efficiency  In 
Bicuspids  And  Molars 


FOREWORD. 

With  the  exception  of  the  anatomical  forms  offered  by  The  Den- 
tists' Supply  Company,  the  porcelain  bicnspid  and  molar  teeth  of  the 
past  seem  to  have  been  designed  to  afford  the  smallest  possible  amount 
of  efficiency  in  mastication. 

The  best  of  them  have  been  copies  of  well  worn  natural  teeth  which 
are  efficient  only  when  firmly  supported  by  healthy  tissues  and  imder 
a  pressure  of  from  150  to  300  pounds.  The  others  have  been  conven- 
tional forms  which  could  be  articulated  only  by  such  grinding  as  de- 
stroyed any  possibility  of  masticating  efficiency. 

Professor  Gysi  believes  that  well  made  full  dentures  are  incapable 
of  exerting  more  than  18  or  20  pounds  of  pressure.  Tt  is  evident  that 
teeth  which  function  only  at  a  pressure  of,  say  150  pounds,  cannot  be 
efficient  at  a  pressure  of  18  pounds. 

Professor  Gysi  has  demonstrated  that  efficient  forms  of  porcelain 
bicuspids  and  molars  can  be  shaped  only  by  applying  nature's  engineer- 
ing principles  to  the  formations  of  the  occlusal  surfaces,  with  such 
modifications  as  the  movable  bases  and  slighter  pressure  require.  He 
has  applied  these  principles  to  the  production  of  Trubyte  bicuspids  and 
molars,  which  are  joined  with  Trubyte  anteriors  to  make  full  sets. 
Such  teeth  cannot  Ix-  ]>rodiiced  by  copying  natural  teeth  because  while 
natural  teeth  present  all  the  necessary  factors  at  different  times  in  their 
history,  they  never  present  all  those  factors  at  any  one  time. 

With  Professor  Gysi's  permission,  and  by  the  aid  of  his  illustra- 
tions, r  have  here  set  forth  in  my  own  words  the  principles  which  un- 
derlie the  formation  of  correctly  formed  porcelain  l)icuspids  and  molars. 


119 


THE  FUNCTIONS  OF  THE  ITATUKAL  BICUSPIDS  AND 

MOLAES. 

Before  we  can  determine  the  requirements  for  efficiency  in  arti- 
ficial teeth,  we  must  understand  the  plan  by  which  nature  causes  the 
natural  teeth  to  discharge  the  several  functions  of  mastication,  and  the 
tasks  of  the  four  groups  of  teeth  in  each  half  of  one  jaw. 

Eor  the  natural  teeth  are  divided  into  groups  by  difference  of 
function  quite  as  effectually  as  they  are  by  formation.  Indeed  the  two 
go  together. 

The  incisors  are  intended  to  bite  the  food  from  the  mass. 

The  cuspids  are  the  guides  of  the  motion  of  the  anterior  part  of 
the  jaw  in  lateral  movements,  and  the  shock  absorbers  in  mastication. 

The  bicuspids  are  the  crackers  of  all  hard  and  brittle  foods  and  the 
tearers  and  separators  of  fibres. 

The  molars  are  designed  to  cut  uj)  the  separated  fibres,  to  isolate 
the  individual  cells  and  crush  the  cell  walls  to  permit  insalivation  of 
the  contents. 

All  teeth  take  part  in  crushing  out  the  fluid  portion  of  foods. 

The  buccal  and  lingual  cusps  of  well  articulated  natural  molars 
interdigitate  so  perfectly,  on  the  "working  side"  during  lateral  occlu- 
sion, as  to  prevent  the  escape  of  solid  portions  of  food.  On  the  opposite 
side,  the  proper  cusps  articulate  to  maintain  balance.  The  cusps  of  both 
sides  articulate  to  maintain  balance  in  the  incising  bite. 

The  occlusal  surfaces  permit  the  escape  of  semi-fluid  portions  of 
food  from  between  grinding  cusps,  and  ready  escape  of  fluid  portions  of 
food. 

Artificial  teeth  which  are  to  be  efficient  in  mastication  must  dis- 
charge these  functions. 


120 


Fig.  58. 
Cracking  action   of  bicuspids. 


Fig.  59. 
Dotted   line   shows   position   of  section   of  molars. 


n 


Fig.  CO. 

Diagram    of    tlie    ridges    of    the    molars    at    dotted    line    in    Fig.    59    which    cut    food. 
Slightly  exaggerated. 


Fig.  Gl. 

The  ridges  as  they  api)ear  in   ponelain   before   tlie  fac'ts   are  sharpened   by   grhuling 
with  carborundum   and  glycerine. 

121 


MODIFICATIONS   OF   IsTATUKAL   FORMS   NECESSARY   IN 
PORCELAIN  TEETH. 

The  fact  that  teeth  for  dentures  and  bridges  will  be  mounted  on 
bases  which  are  either  movable  or  less  in  number  and  strength  than  the 
full  number  of  roots  in  healthy  tissues,  makes  it  impossible  for  them  to 
transmit  the  heavy  pressures  possible  to  natural  teeth.  Probably  dent- 
ures cannot  exert  more  than  1/10  of  the  average  power  of  healthy  nat- 
ural teeth,  and  bridges  from  Y4  to  possibly  Yi.  This  great  difference  in 
transmitted  power  requires  certain  changes  in  form  to  make  the  porce- 
lain teeth  efficient  at  small  pressures. 

The  relatively  broad  opposing  planes  of  well  worn  natural  teeth 
cannot  be  made  efficient  at  the  pressure  possible  to  dentures  and  bridges, 
because  not  enough  power  can  be  exercised  to  force  such  large  areas  to 
tear,  cut  and  grind  the  food.  A  larger  number  of  small,  relatively  sharp 
areas  must  be  substituted  for  the  few  large  ones,  and  these  must  inter- 
act, as  between  uppers  and  lowers,  in  such  way  as  to  discharge  the 
proper  cutting  and  grinding  functions. 

The  cusps  must  be  high,  as  they  are  in  newly  erupted  teeth,  but 
with  the  important  difference  that  the  depth  of  bite  must  be  less  than 
in  any  sharp  natural  teeth,  in  order  that  dentures  and  bridges  may  not 
be  dislodged  by  lateral  stress. 

The  three  molars  in  the  perfect  natural  denture  must  be  replaced 
by  two  in  the  artificial  denture,  requiring  some  modification  in  form. 

The  fossae  must  be  deep  to  permit  escape  of  partly  ground  food 
from  between  the  cusps  but  not  from  between  the  teeth.  The  sulci  must 
be  deep  to  permit  the  rapid  escape  of  fluids  and  a  shallow  bite. 

The  teeth  must  be  so  carved  as  to  be  easy  to  arrange  on  any  articu- 
lator or  for  any  case  and  to  render  the  best  service  possible  under  the 
conditions,  when  the  dentist  desires  to  merely  occlude  them  and  not  to 
articulate  them. 

WHAT  CONSTITUTES  DEPTH  OF  BITE. 

The  depth  of  bite  is  the  distance  the  teeth  move  vertically  in  articu- 
lation. 

There  are  three  depths  of  bite  to  each  tooth,  the  "working"  bite, 
the  "incising"  bite  and  the  "balancing"  bite. 

The  working  bite  is  the  shallowest  and  the  balancing  bite  the  deep- 
est.    The  incising  bite  is  between  the  two. 

The  working  and  balancing  bites  are  described  on  the  following 
pages.     The  incising  bite  needs  no  description. 

122 


FIVE   STAGES   OF  WEAR  OF  NATURAL  TEETH. 


A.  Unworn  Stage.  Newly  erupted  natural  teeth  exhibiting  high  cusps  and 
deep  fossae  and  sulci  with  deep  bite.  These  teeth  are  efficient  with  the  relatively 
small  muscular  power  of  the  child,  but  have  not  been  worn  to  perfect  articula- 
tion.   The  bite  is  far  deeper  than  is  practicable  in  artificial  teeth. 

B.  Gkeate.st  Ekficip;xcy  Sta(;e.  Natural  teeth  worn  to  the  stage  of  greatest 
efficiency.  Wear  has  shaped  sharp  edged  facets  on  the  cusps,  which  are  very 
efficient  in  cutting  up  fibres  and  in  providing  rolling  surfaces  for  grinding  cells. 
This  is  the  stage  of  wear  reproduced  in  Trubyte  teeth.  The  bite  in  the  natural 
teeth  at  this  stage  is  deeper  than  can  be  advantageously  employed  in  artificial 
teeth. 

C.  Reuuced  Efficiency  Stage.  Wear  has  formulated  such  broad  opposing 
planes  on  the  molars  that  they  can  be  forced  through  the  food  only  by  the 
exercise  of  great  power.  The  cutting  action  of  the  molars  is  now  limited  to 
the  action  of  the  edges  of  the  few  sulci.  In  persons  of  great  muscular  power, 
these  teeth  will  be  efficient  in  grinding. 

The  bite  has  been  worn  shallow  but  the  opposing  areas  are  much  too  broad 
to  be  forced  through  food  by  the  exercise  of  the  relatively  slight  power  possible 
to  dentures. 

This  is  about  the  degree  of  wear  which  has  been  advocated  for  the  forms  of 
artificial  teeth.  Such  formations  for  porcelain  bicuspids  and  molars  is  now 
known  to  make  efficiency  impossible  to  the  dentures. 

D.  Mi(  H  Wou.\  STACiE.  The  bite  is  shallow  but  the  opposing  areas  are 
broad  and  require  the  exertion  of  great  force  to  make  them  efficient. 

E.  Stage  of  Extkkme  Weak.  Tlio  cutting  power  is  possible  only  by  the 
making  of  extreme  movements  and  the  exercise  of  great  force. 

Trubyte  terth  exliibit  the  stage  of  wear  shown  in  Figure  Aand  the  depth  of 
bite  Hliown  in  Figure  j/. IJ) 


123 


THE  WOKKING  BITE. 

The  depth  of  this  bite  is  the  distance  the  lower  teeth  on  the  work- 
ing side  move  vertically  in  passing  from  the  position  of  central  occlu- 
sion to  that  of  lateral  occlusion,  or  vice  versa. 

The  distance  the  teeth  move  vertically  is  determined  by  the  degree 
of  vertical  inclination  of  the  occlusal  grooves  of  either  set  as  they  pass 
from  the  main  longitudinal  groove,  upward  over  the  buccal  or  lingual 
margin  of  the  tooth. 

Figure  65  on  the  opposite  page  represents  cross  sections  of  Trubyte 
upper  and  lower  molars  in  central  occlusion.  JSTote  that  the  upper 
lingual  cusp  does  not  reach  the  bottom  of  the  fossa  in  the  lower  tooth, 
and  the  lower  buccal  cusp  does  not  reach  the  deepest  part  of  the  fossa 
in  the  upper  tooth.  When  these  teeth  move  into  a  position  of  lateral 
occlusion,  as  shown  in  Figure  68,  the  slightly  inclined  buccal  groove  on 
the  lower  tooth  articulates  with  the  relatively  flat  lingual  incline  of  the 
buccal  cusp  of  the  upper  tooth,  and  causes  the  lower  teeth  to  move  verti- 
cally downward,  through  the  distance  from  Point  1  to  Point  2.  The 
slightly  inclined  lingual  groove  on  the  lower  tooth  articulates  with  the 
upper  lingual  cusp.  This  does  not  increase  the  vertical  movement  of 
the  lower  teeth. 

The  movement  of  the  whole  jaw  is  illustrated  in  Figure  67.  The 
lower  central  incisor  has  moved  downward  from  the  position  occupied 
by  the  dotted  outline  of  that  tooth.  The  depth  of  the  bite  in  the  first 
molars  is  here  less  than  in  the  incisors,  and  is  equal  to  the  vertical  dis- 
tance from  the  Point  1  to  Point  2. 

The  relative  vertical  distances  moved  by  the  central  incisor  and 
the  left  condyle  are  shown  in  Figure  69.  It  will  be  seen  that  the  condyle 
has  moved  downward  very  little.  This  movement,  combined  with  the 
movement  of  the  molars  through  the  opposing  grooves,  as  shown  in 
Figure  68,  results  in  the  working  bite  being  very  shallow,  provided  the 
teeth  are  carved  to  articulate  properly. 

Figure  70  illustrates  the  movements  of  the  several  parts  of  the 
condyles  and  teeth  in  extreme  lateral  position  as  seen  from  the  side  and 
from  above.  The  left  condyle  has  moved  strongly  out  of  the  fossa, 
while  the  right  condyle  has  moved  forward  and  inward.  This  lateral 
movement  has  an  important  influence  on  the  depth  of  bite.  When  it 
is  present  in  considerable  degree  the  bite  is  shallow.  When  it  is  absent, 
the  bite  is  required  to  be  deeper  to  maintain  the  necessary  relations 
between  the  dentures. 

The  depth  of  the  working  bite  in  Trubyte  teeth  has  been  deter- 
mined on  an  engineering  basis.  It  is  much  shallower  than  in  any  good 
specimens  of  natural  teeth,  or  any  other  artificial  teeth  which  even  ap- 
proach the  principles  of  efficiency  as  here  laid  down.  It  is  adapted  to 
the  average  inclination  of  the  downward  path  of  the  condyle  (33  de- 
grees) the  average  inclination  of  the  inward  lateral  path  (16  degrees) 
and  the  inclination  of  the  incisor  incline  most  advantageous  in  artificial 
teeth  (40  degrees). 

(Continued  on  Page  126) 

124 


The  depth   of  the  working 
bite  is  from  1  to  3. 


BALANCING 
BITE 


^pWORK 
/     BITE 


ING 


Fig.  66. 
Uelations  of  the  first  molars  in   working  bite. 


WORKING  BITE     LEFT  SIDE 
Fig.  t)7. 


Fig.   OS. 

Note   articulation    of   cusps 

and  grooves. 


'M-1 


=  1:2 


Fig.   CD. 
ln<i.sor  and  condyle  movements  in   working  bite. 


/J    BALANCING 
^       BITE 


Fig.  70. 
I£ — VVrtlcal  movement  of  iidvanclng  condyle. 
L— Vertlcjil  movement  of  stationary  condyh'. 
In  the  icutor  ;i  diagram  of  molar  ainl   Incjsor  movements  in  extreme  lateral  occlusion 


125 


Proper!}^  articulated  Trubyte  teeth  will  be  found  to  move  vertically 
a  shorter  distance  than  any  other  teeth  in  the  working  bite,  and  to  prac- 
tically preclude  the  occurrence  of  undue  lateral  strains  on  dentures  or 
abutments. 

It  is  not  necessary  to  provide  bicuspids  and  molars  with  different 
depths  of  bite  for  different  inclinations  of  the  condyle  paths.  When  the 
teeth  have  been  articulated,  the  necessary  changes  in  the  occlusal  sur- 
faces can  be  easily  and  quickly  made  by  grinding  the  sets  together  with 
carborundum  powder  and  glycerine.  This  process,  Avhich  should  be 
followed  in  all  cases,  will  make  adaptations  which  could  not  be  made  in 
carving  or  by  other  forms  of  grinding. 

THE  BALANCING  BITE. 

The  depth  of  this  bite  is  the  distance  the  lower  teeth  on  the  balanc- 
ing side  move  vertically  to  maintain  balancing  relations  between  the 
dentures  during  articulation.  It  is  much  greater  than  the  depth  of  the 
working  bite,  because  the  steep  lingual  inclines  of  the  lower  buccal  cusps 
articulate  with  the  steep  inclines  of  the  lingual  cusps  of  the  upper  teeth, 
and  because  the  lower  cusps  often  travel  directly  across  the  steepest 
parts  of  the  upper  cusps  instead  of  following  the  sulci. 

Figure  Xo.  71  on  the  opposite  page  shows  upper  and  lower  Trubyte 
molars  in  central  occlusion.     "D"  equals  the  depth  of  bite. 

In  Figure  Xo.  72  the  left  lower  molars  have  moved  into  the  posi- 
tion of  the  extreme  balancing  bite,  through  the  vertical  distance  1-3 
in  Figure  Xo.  71. 

Figure  Xo.  73  shows  the  relations  of  all  the  teeth  on  the  balancing 
side.  The  lower  jaw  has  moved  downward  to  the  right,  away  from  the 
observer.  The  buccal  cusps  of  the  lower  bicuspids  have  climbed  the 
lingual  cusps  of  the  upper  bicuspids.  The  middle  buccal  cusp  of  the 
lower  first  molar  has  climbed  the  mesio-lingual  cusp  of  the  upper  first 
molar.  The  m6sio-buccal  cusp  of  the  lower  second  molar  has  climbed 
the  disto-lingual  cusp  of  the  upper  first  molar.  The  distal  buccal  groove 
of  the  lower  second  molar  has  climbed  the  long  lingual  cusp  of  the  up- 
per second  molar. 

Figure  Xo.  74  shows  the  vertical  distance  which  the  condyle  on  the 
balancing  side  has  traveled  downward  from  its  position  of  rest  in  cen- 
tral occlusion. 

Figure  Xo.  75  shows  the  movements  of  the  two  condyles  as  seen 
from  the  side  and  the  movements  of  the  condyles  and  teeth  as  seen  from 
above.     The  lateral  movements  of  both  condyles  are  here  plainly  shown. 

Different  inclinations  of  the  condyle  and  incisor  paths  require  only 
minute  adaptations  of  the  teeth  to  the  balancing  bite.  Such  adapta- 
tions cannot  be  well  made  by  carving  or  grinding  with  a  stone,  but  they 
can  be  quickly  made  by  rubbing  the  articulated  sets  together  in  carbor- 
undum powder  and  glycerine. 

126 


Ecr; 


Fig.  71. 
Depth  of  balanfiug  bite  is;  frdin  1  to 


Fig.  72. 
Relations  of  first  molars  in  balancing  bite. 


=  1:3 


BALANCING  BITE     LEFT  SIDE 


Fig.  7:;. 
The  centrals  have  moved  from  the   position   shown   by  the  central  in   dotted  outline. 


Fig.  74. 
A'ertii'al    dcptli    of   condyle   and    incisor   movements   in    the   balancing    bite. 


BALANCING 
BITE 


U 

-(^WORKING 
^      BITE 


Fig.   7.-.. 
K      Vcrfl<'al    niovciiK-nt    of    stationary    coinlyh-. 
L     \'crtl<"il    iiiovcnicrit    of    advaiK-ing    condyle.      In    llic 
Inclnrjr  liioveiiicntH   in   extreme    lateral    occlusion. 


'Mtcr  a   diagi'am   of  molar  and 


127 


PEOPEE  FOEMATIOI^r  OF  CUSPID  EDGES. 

It  may  seem  a  little  late  to  refer  here  to  the  formation  of  the  edges 
of  the  cuspids,  since  from  some  points  of  view  they  should  have  been 
discussed  in  Part  11.  But  they  are  the  most  anterior  teeth  in  which  the 
application  of  engineering  principles  effects  important  changes  of  form. 

The  upper  and  lower  cuspids  are  probably  the  most  difficult  teeth 
in  either  dentures  or  bridges  to  place  in  right  relations.  They  are 
wrongly  placed  in  99  cases  out  of  100  and  neither  dentist  nor  patient 
is  the  wiser.  But  when  they  are  rightly  shaped  and  placed,  the  stabil 
ity  and  efficiency  of  the  dentures  are  so  increased  as  to  yield  gratifying 
results. 

Properly  formed  artificial  upper  cuspids  exhibit  relatively  long 
mesial  cutting  facets  and  a  shorter  distal  facet.  Properly  formed 
artificial  lower  cuspids  exhibit  a  short  mesial  cutting  facet  and  a  rela- 
tively long  distal  facet. 

The  short  facet  on  the  mesial  surface  of  the  lower  cuspid  should 
both  occlude  and  articulate  with  a  short  distal  facet  on  the  cutting  edge 
of  the  upper  lateral.  A  long  facet  on  the  mesial  side  of  the  upper  cuspid 
should  both  occlude  and  articulate  with  a  long  facet  on  the  distal  surface 
of  the  lower  cuspid.  And  the  short  facet  on  the  distal  surface  of  the 
upper  cuspid  should  articulate  with  the  mesial  facet  on  the  buccal 
cusp  of  the  lower  first  bicuspid.  In  other  words,  the  upper  lateral  and 
cuspid  should  occlude  with  the  lower  cuspid  when  the  jaw  is  in  central 
position,  and  during  articulation  these  relations  should  continue  un- 
disturbed.    Figure  76. 

The  purpose  of  these  relations  is  to  guide  the  anterior  part  of  the 
lower  jaw  during  lateral  movements,  and  to  take  up  the  shock  when 
the  upper  and  lower  jaws  come  into  contact.  For  when  the  lower  jaw  is 
moved  downward,  sideways  and  upward  against  the  upper  jaw  in  the 
position  of  lateral  occlusion,  the  jaws  come  into  contact  first  and  with 
greatest  force  at  the  cuspids.  And  only  as  the  jaw  starts  back  to  the 
position  of  central  occlusion  do  the  bicuspids  and  molars  come  into  pow- 
erful contact.  Hence  the  importance  of  correctly  placed  cuspids,  to 
either  dentures  or  bridges. 

This  articulation  of  the  cuspids  serves  another  important  purpose. 
When  food  has  been  bitten  from  the  mass  by  the  incisors,  it  is  started 
toward  the  back  of  the  mouth  by  the  action  of  the  tongue  and  cheeks. 
When  the  jaws  are  separated,  the  action  of  the  tongue  and  cheeks  is  to 
place  morsels  lengthwise  of  the  teeth.  The  cuspids  coming  into  contact 
before  the  other  teeth,  seize  and  hold  the  anterior  ends  of  such  morsels. 
The  molars,  as  they  come  into  contact,  hold  the  posterior  ends,  and  thus 
the  fibres  are  held  stretched  while  the  bicuspids  with  their  peculiar 
open  and  shut  articulation,  come  down  upon  them,  to  stretch  and  tear 
them  apart,  and  pierce  between  them. 

The  articulation  of  the  cuspids  will  be  more  fully  considered  under 
the  subject  of  articulation.  But  it  should  be  remembered  that  unless 
the  cutting  edges  have  been  properly  formed,  they  cannot  be  properly 
occluded  or  articulated  and  the  discharge  of  their  important  functions 
is  rendered  impossible. 

128 


Fig.  77. 
Proper  relations  of  upper  and  lower  cus- 
pids in  articulation. 


CUSPID 

RELATIONS   ON/ 
THE  WORKING      /    r^j^ 
SIDE  IN  LATERAL/      ^""^ 
ARTICULATION 


Q 


-'■•t-t-t-*- 


Fig.  79. 
I'^icets    on    ujiper    centrals,    laterals    and 
■tispids. 


Fig.  7S. 
How    the    faifts    on    artitici.-il    upper    cii> 
pids   must   slniic. 


129 


CEACKIisTG  AND  TEAEING  POWER  IN  THE  BICUSPIDS. 

The  human  bicuspids  are  the  lineal  descendants  of  the  bone  crack- 
ing teeth  in  meat  eating  animals  like  the  dog,  Figure  80,  and  are 
given  their  special  location  in  the  denture  that  they  ma)'  crack  all  hard 
and  brittle  foods  and  tear,  stretch  and  separate  all  fibres. 

In  order  that  these  teeth  may  crack  all  hard  and  brittle  foods,  it 
is  essential  that  the  occlusal  surface  of  each  bicuspid  shall  be  formed 
into  a  grain  trap  for  holding  small  seeds  and  grains,  and  that  the  two 
adjoining  bicuspids  shall  form  traps  for  holding  similar  articles  of  food 
too  large  for  one  tooth,  as  is  shown  in  Figure  81.  The  occlusal  sur- 
face of  a  properly  formed  bicuspid  will  therefore  present  two  small 
traps  like  that  diagrammatically  illustrated  in  Figure  82  on  the  oppo- 
site page.  Only  such  a  form  as  this  will  prevent  the  escape  of  small 
grains  as  the  upper  and  lower  teeth  come  together.  Such  a  formation  is 
shown  in  Figure  84. 

The  tearing  action  of  the  bicuspids  on  fibres  is  made  possible  by 
the  formation  of  the  occlusal  surfaces  and  the  peculiar  open  and  shut 
form  of  articulation,  which  will  be  more  fully  considered  later.  The  cus- 
pids come  into  contact  first  during  articulation,  and  the  molars  come  into 
contact  before  the  lingual  cusps  of  the  bicuspids  do,  and  hold  fibres 
firmly  at  both  ends,  while  the  bicuspids,  with  their  open  and  shut  ar- 
ticulation, stretch  the  fibres,  tear  one  from  another,  and  pierce  between 
and  separate  them.  This  tearing  action  is  diagrammatically  illustrated 
in  Figure  85. 

Trubyte  bicuspids  have  been  designed  with  a  knowledge  of  these 
functions  and  so  shaped  as  to  discharge  them  with  the  exercise  of  slight 
force.  So  far  as  I  know,  they  are  the  first  bicuspids  which  have  ever 
been  designed  with  any  intelligent  understanding  of  the  functions  they 
must  perform. 


130 


Fig.  SO. 
Tbe    bone    craekini;-    teeth    of    the    d 


Pig.  81. 
Similar    i-raeking    action    by    human    bi- 
cuspids. 


>  •*!»  i 


X' 


Fig.  S3. 
Lingual    cusps    open    to    receive    seeds 
and  grains. 


Fig.  s-J. 
Diagraniniatic    representatidn    (if    a    grain 
trap.      Samo    trap    in    Trubyte    bicnsjiids. 


Fig.  84. 
Ituccal    cusps    interdigltate    in    articulation. 


Fig.  S.-.. 
Diagram    of    tearing    action. 


131 


CUTTING  AND  GEINDING  POWER  IN  THE  MOLARS. 

The  functions  of  the  molars  are  to  hold  the  posterior  ends  of 
fibers  which  are  being  torn  bj  the  bicuspids,  to  cut  the  torn  fibers  into 
short  pieces,  and  to  roll  fibers  in  such  way  as  to  isolate  individual  cells 
and  smash  the  cell  walls  to  permit  insalivation.  The  importance  of 
this  smashing  power  is  seen  when  it  is  understood  that  starches  which 
have  not  been  insalivated  are  not  digested. 

Artificial  molars  are  enabled  to  discharge  these  functions  by  a 
smooth  sliding  articulation,  which,  in  its  form  of  greatest  efficiency, 
opposes  a  number  of  small,  relatively  sharp  facets  in  such  way  that 
they  interact  to  produce  the  required  effect. 

The  efficiency  of  the  molars  in  cutting  will  be  determined  in  no 
small  degree  by  the  manner  in  which  these  facets  interact.  If  they 
merely  press  directly  against  each  other,  their  efficiency  will  be  small. 
If  they  can  be  made  to  draw  across  each  other,  as  one  draws  a  knife  in 
cutting  a  substance,  the  efficiency  will  be  greatly  increased.  The  ideal 
of  cutting  efficiency  is  diagrammatically  shown  in  Figure  86  on  the 
opposite  page. 

The  grinding  power  of  the  molars  is  dependent  on  the  continued 
opposition  or  contact  of  the  facets  during  the  time  that  the  molars  are 
returning  from  lateral  occlusion  to  central  occlusion.  Such  opposition 
or  contact  is  made  possible  only  by  the  application  of  engineering  prin- 
ciples to  the  formation  of  occlusal  surfaces  which  will  interact  with 
the  necessary  accuracy  and  efficiency. 

The  occlusal  surfaces  should  exhibit  deep  fossae  to  permit  the 
escape  of  partly  ground  food  from  between  the  facets  but  not  from 
between  the  teeth.  This  leaves  only  fibers  and  unground  cells  between 
the  facets. 

The  sulci  should  be  deep  to  permit  easy  escape  of  such  portion  of 
the  food  as  has  been  rendered  fluid. 

The  dentist  should  not  expect  that  the  manufacturer  can  furnish 
him  porcelain  teeth  which  are  exactly  designed  for  the  conditions 
peculiar  to  any  given  case  or  to  his  own  methods  of  arrangement.  Dif- 
ferences in  the  kind  of  articulator  used,  in  the  manner  of  setting  up, 
in  the  lateral  path,  in  the  location  of  the  rotation  points  and  other 
factors,  will  render  slight  modifications  of  the  form  of  the  teeth  neces- 
sary. The  highest  degree  of  efficiency  in  the  dentures  requires  that 
the  dentist  make  these  minute  adjustments  himself. 

But  the  manufacturer  can  furnish  teeth  which  are  correct  in 
proportions,  in  shallowness  of  bite,  in  height  of  cusps  and  depth  of  foss?e 
and  sulci.  Most  important  of  all,  he  can  furnish  teeth  with  properly 
interacting  ridges  and  facets,  so  that  the  grinding  of  what  may  be  called 
the  individual  facets  on  the  teeth  shall  be  only  their  modification  to  the 
peculiarities  of  the  case  in  hand. 

132 


Fig.  87. 
Food  cells  are  isolated  and  the  cell  walls 
broken  by  the  rubbing  together  of  the 
facets.  The  rubbing  action  is  diagram- 
niatically  shown  by  the  mortar  and  pestle 
in   which  substances  are  pulverized. 


Fig.  SC. 
Diagrammatic  illustration  of  the  cutting 
action  exhibited  by  oppo.sed  ridges  and 
facets  in  Trubyte  molars.  If  the  point  A 
f>f  the  upper  block  be  carried  to  the  point 
C  of  the  lower  block,  and  then  the  upper 
block  be  so  moved  as  to  bring  the  point 
B  directly  over  the  point  D  of  the  lower 
block,  each  of  the  opposed  ridges  will  cut 
throughout  its  length  with  a  drawing  mo- 
tion. This  is  the  longest  and  most  efficient 
"cut"   possible  to  these  ridges. 


Fig.  88. 
Diagrammatic  representation  of  the  plan 
on  which  artificial  molars  have  generall.y 
been  Hha[)ed  In  the  past.  T'lii!  f)road  sur- 
faces can  not  cut  up  foods  to  isolates  the 
cells,  'i'ticy  can  be  appro.vimated  only  by 
the   e.verclse   of   great   force. 


Fig. 
A.  A  cross  section  o 
and  second  nudars  sh 
each  tooth.  1'..  Kidgc 
byte  upper  and  lower 
The  cross  sections  sho 
at     the    dotted     line    iu 


mbyte  1 
ng  five 
nd  facet 
dars  opi 
above  w 
s    ligiire. 


iwer  tirst 
ridges  in 
■i  in  Tru- 
losed.  C. 
ere  made 


133 


the  impossibility  of  geinding  improperly 

formed  teeth  to  proper  bites  or  to 

efficie:^[T  forms. 

If  teeth  are  not  given  the  correct  depth  of  bite  bv  the  manufacturer 
and  carved  to  efficient  forms,  it  is  practically  impossible  for  the  dentist 
to  grind  them  to  advantageous  bites,  or  to  efficient  forms  of  masticating 
surface,  as  is  made  plain  by  Figure  90  on  the  opposite  page. 

Figure  A  shows  the  occlusal  surfaces  of  upper  and  lower  molars 
ground  to  articulating  form  after  the  method  formulated  by  Dr. 
Bonwill.  It  will  be  noted  that  this  method  grinds  a  broadly  con- 
cave occlusal  surface  on  each  of  the  molars.  Figure  B  shows 
the  same  molars  occluded.  It  will  be  noted  that  very  broad  opposing 
planes  are  brought  into  contact,  such  as  could  be  made  efficient  only 
by  the  exercise  of  a  force  which  neither  bridges  nor  dentures  can  trans- 
mit. The  cracking  and  cutting  formations  which  have  been  described 
are  entirely  lacking,  and  no  escapeways  are  provided  for  semi-fluid 
food. 

It  is  impracticable  for  the  dentist  to  grind  buccal  cusps  and  grooves 
which  shall  interact  properly,  and  articulation  is  attained  only  by  cusp 
climbing  cusp.  The  buccal  cusp  of  the  lower  molar  must  climb  the 
long  overhanging  buccal  cusp  of  the  upper  molar.  This  necessitates  a 
marked  vertical  movement  even  in  the  working  bite.  The  bite  of  the 
teeth  is  therefore  deep,  and  dentures  articulated  after  this  manner  are 
easily  displaced. 

Figure  C  shows  a  longitudinal  section  of  the  same  teeth.  The 
broad  occlusal  surfaces  and  the  absence  of  cracking,  tearing  and  cutting 
formations  are  plainly  seen.  This  is  the  only  form  to  which  improperly 
formed  teeth  can  be  ground  with  a  stone.  Unfortunately  there  are  still 
dentists  who  use  teeth  thus  ground. 

Figure  D  shows  the  occlusal  surfaces  of  the  anatomical 
moulds  of  The  Dentists'  Supply  Company.  These  are  carved  to  much 
more  nearly  correct  anatomical  form  than  were  the  teeth  of  Dr.  Bon- 
will's  time.  The  elevations  of  the  cusps  are  more  nearly  correct, 
and  sulci  and  fossae  are  provided  for  the  escape  of  food  and  for  the 
articulation  of  the  cusps  of  one  set  with  the  grooves  of  the  opposing  set. 

Figure  E  shows  the  molars  occluded.  The  longitudinal  groove 
is  entirely  different  in  character  than  that  shown  in  Figure  B.  The 
upper  lingual  cusp  and  the  lower  buccal  cusp  no  longer  reach  the  bottom 
of  the  fossse.  Escapeways  are  provided  for  partly  ground  food  and 
buccal  and  lingual  grooves,  through  which  the  opposing  teeth  move. 
The  upper  buccal  cusp  does  not  overhang  the  lower  molar  as  in  Figure 
B.  The  depth  of  bite  in  these  teeth  is  only  half  as  great  as  in  those 
shown  in  Figure  B. 

134 


Fig.    90. 


Figure  F  shows  a  longitudiual  section  of  the  same  teeth, 
with  the  smaller  opposed  surfaces,  the  proper  relations  of  cusps  and 
grooves,  and  the  escapeways  for  food.  These  teeth  were  a  great  improve- 
ment over  the  forms  in  Figure  C. 

Figure  G  shows  the  occlusal  surfaces  of  Trubyte  teeth,  with 
the  formations  for  cracking,  tearing  and  cutting  which  have  been 
described. 

Figure  H  shows  Trubyte  first  molars  occluded.  The  character  of 
the  longitudinal  main  groove  and  of  the  cusps,  has  been  entirely  changed 
by  making  the  cuspal  inclines  which  form  that  groove,  convex,  in  l)oth 
the  upper  and  lower  teeth.  The  convex  surfaces  of  the  several  cusps 
prevent  the  opposing  cusps  reaching  the  deepest  parts  of  the  fosssp,  and 
provide  large  escape  ways  for  partly  crushed  food.  The  upper  buccal 
cusp  overhangs  to  only  half  the  vertical  depth  of  the  buccal  cusp  in  the 
anatomical  moulds  and  one-quarter  the  depth  of  the  same  cusp  ground 
after  Dr.  BonwilFs  plan.  The  bite  is  proportionately  less  deep  and 
dentures  made  with  these  teeth  are  less  easily  dislodged. 

Figure  I  shows  a  longitudinal  section  of  these  teeth.  Instead  of 
presenting  the  flat  opposed  surfaces,  shown  in  Figure  C,  or  the  single 
convex  surfaces  shown  in  Figure  F,  these  teeth  exhibit  from  two  to  five 
grooves,  and  from  three  to  six  cusps  each.  The  cusps  and  cuspal  ridges 
are  accurately  opposed  to  grooves  in  the  other  set. 

The  grooves  present  escapeways  for  fluids  or  semi-fluid  food,  and 
wlien  the  articulated  teeth  have  been  rubbed  together  with  glycerine  and 
car])orundum  to  form  tiny,  sharp  edged  facets  on  each  of  these  cuspal 
ridges,  the  tearing,  cutting  and  grinding  powers  are  the  greatest  possil)le 
to  j)f)rcelain  teeth. 

135 


PART   V. 


The 
Selection  Of  An  Articulator 


FOREWORD. 

The  articulation  of  the  adult  natural  teeth  probably  determines 
the  formation  of  the  articulating  surfaces  in  the  condyles  and  fossae, 
the  muscular  actions,  and  the  habitual  masticating  movements  of  the 
jaw.  The  arrangement  of  the  artificial  teeth  will  determine  whether 
the  patient  shall  be  enabled  to  continue  those  movements,  which  are  the 
most  efficient  he  will  ever  have,  or  whether  these  movements  shall  be 
destroyed,  with  a  strong  probability  that  other  efficient  movements 
cannot  be  substituted. 

Teeth  are  articulated  when  they  are  arranged  to  maintain  grinding 
and  balancing  relations  with  the  masticating  movements  peculiar  to 
the  patient  for  whom  they  are  intended.  If  the  work  is  intelligently 
done,  the  patient  is  enabled  to  continue  the  habitual  masticating  move- 
ments. The  use  of  the  dentures  or  bridges  is  learned  with  comparative 
ease.  The  patient  is  given  the  greatest  possible  masticating  power,  and 
food  may  be  properly  prepared  for  digestion. 

Teeth  are  occluded  when  they  are  arranged  merely  for  the  opening 
and  closing  movement.  Occluded  dentures  generallj^  destroy  the  effi- 
cient masticating  movements  habitual  to  the  patient,  and  finally  destroy 
the  formation  of  the  articulating  surfaces  which  were  essential  to  the 
continuance  of  those  movements.  They  rarely,  if  ever,  substitute  efficient 
masticating  movements.  And  it  is  common  history  for  patients  with 
occluded  dentures  to  lose  all  definite  control  of  the  jaw  movements. 
It  is  difficult  for  patients  to  learn  to  use  such  dentures,  and  the  fact 
that  some  do  finally  learn  is  rather  a  tribute  to  the  marvellous  adaptive 
power  of  the  human  frame  than  to  the  dentist's  skill.  The  average 
masticating  power  of  occluded  dentures  is  slight. 

The  dentist  practically  determines  what  quality  of  service  he  will 
render  liis  patients  when  he  selects  an  articulator,  because  the  limita- 
tions of  the  appliance  become  his  limitations.  The  selection  of  the 
articulator  is  therefore  very  important. 

]My  owTi  belief  is  that  in  every  case  where  the  patient  can  be  brought 
to  see  the  benefits  of  superior  service  and  to  pay  a  fee  which  permits 
such  service,  the  dentist  should  determine  and  reproduce  the  movements 
of  the  patient's  jaw  and  arrange  the  teeth  to  harmonize  with  those 
movements. 

I  believe  also  that  it  costs  the  dentist  little,  if  any  more,  to  articulate 
the  teeth  so  that  they  will  be  satisfactory  from  the  beginning,  than  to 
grind  and  fit  and  remake  occluded  dentures  in  the  effort  ''to  make 
them  do." 

In  cases  where  such  service  is  not  possiljle,  the  dentist  should 
arrange  the  teeth  in  harmony  with  average  masticating  movements, 
especially  since  this  takes  Ijut  little  more  time  tlian  to  merely  occlude 
them. 

I  liave  endeavored  to  set  forth  in  this  section  the  reasons  why 
articulators  which  meet  certain  requirements  (do  not  confuse  that  with 
certain  articulators^  should  be  used. 

139 


SELECTIXG  AX   ARTICULATOR 

It  seems  to  me  that  an  articulator  cannot  be  intelligently  selected 
witliont  at  least  an  elementary  knowledge  of  the  normal  jaw  movements 
in  biting  and  mastication,  a  knowledge  of  some  of  the  changes  effected 
in  those  movements  bv  the  irregular  loss  of  the  natural  teeth,  and  a 
knowledge  of  the  limitations  of  the  articulator  itself. 

An  articulator  is  a  mechanical  device  in  which  artihcial  teeth 
niav  be  arranged  to  articulate  in  the  mouth.  In  order  that  teeth  mav 
be  articulated,  it  must  reproduce  the  masticating  movements  of  the  jaw 
with  at  least  reasonable  accuracy.  If  it  is  capable  of  only  the  opening 
and  closing  movements,  it  cannot  reproduce  the  movements  of  articula- 
tion, and  is  therefore  merely  an  occluding  frame. 

It  is  not  necessary  that  an  articulator  should  resemble  in  form  the 
human  jaw,  as  some  have  thought,  or  that  it  be  mounted  with  the  upper 
artiticial  jaw  fixed  and  the  lower  movable,  as  others  have  held.  If  it 
reproduces  with  reasonable  accuracy  the  more  important  jaw  move- 
ments, it  makes  little  difference  how  unlike  the  jaw  in  appearance  it 
may  be. 

The  first  important  step  for  him  who  would  select  an  articulator 
intelligently,  is  to  know  what  are  the  more  important  jaw  movements 
to  which  the  teeth  will  be  sul)jected  when  they  are  placed  in  the  mouth. 
The  jaw  movements  in  order  of  importance  from  least  to  greatest  are  the 
straight  opening  and  closing,  the  incising  and  the  lateral  movements  of 
mastication. 

I  l)elieve  that  the  character  of  these  movements  has  been  exhaust- 
ively known  for  less  than  10  years.  At  least  the  facts  which  have  been 
learned  within  that  period  have  greatly  extended  our  knowledge  and 
have  permitted  the  construction  of  articulators  which  reproduce  the 
movements  with  greater  accuracy  than  those  of  earlier  days. 

The  present  knowledge  of  these  movements  is  the  result  of  the 
labors  of  many  workers.  Without  disparaging  the  labors  of  any  others, 
T  wish  to  call  especial  attention  to  the  lal)ors  of  two  men,  Mr.  Xorman 
G.  Jjennctt  and  J'rof.  Dr.  (jlysi,  since  they  establish  two  points  of  the 
utmost  importance,  as  follows : 

1.  An  articulator  in  whicli  the  upper  jaw  hinges  or  rotates  on 
the  condyles  cannot  properly  reproduce  the  average  opening  or  lateral 
movements. 

2.  An  articulator  which  is  to  accurately  reproduce  the  movements 
peculiar  to  any  given  patient,  must  have  rotation  ])oints  wliich  are 
movable  at  least  in  certain  directions. 

Such  conclusions  could  be  i-eached  only  after  acciii'at(!ly  recording 
the  movements  of  many  jaws.  It  will  be  woi-th  while,  therefore,  to 
see  how  such  movements  were  accurately  recorded. 

141 


HOW   THE   JAW  MOVEMENTS   WERE   RECORDED. 

Mr.  Bennett  recorded  the  movements  of  the  several  parts  of  the 
jaw  by  projecting  the  illumination  of  lights  fixed  over  those  points  on 
the  walls  and  ceiling.  By  an  elaborate  mathematical  demonstration,  he 
showed  that  the  recorded  movements  could  not  be  reproduced  with  the 
condyles  as  centers,  but  that  the  different  movements  had  many  centers 
in  different  locations.  So  wide  apart  were  some  of  the  locations  that  he 
doubted  whether  a  practicable  articulator  could  take  cognizance  of 
them. 

Prof.  Gysi  and  his  assistants  gave  almost  two  weeks  of  continuous 
labor  to  confirming  the  discoveries  by  Mr.  Bennett,  and  to  devising 
methods  whereby  jaw  movements  could  be  more  easily  recorded.  Prof. 
Gysi  has  lost  some  of  the  posterior  teeth  on  either  side  of  his  lower  jaw. 
He  made  a  partial  plate  which  fitted  the  spaces,  and  which  could  be 
clamped  firmly  in  place  by  means  of  bands  around  teeth  adjoining  the 
spaces.  Stiff  wires  from  both  sides  of  this  plate  were  brought  to  the 
median  line  of  the  mouth  where  they  passed  out  between  the  lips. 
These  wires  were  continued  in  to  three  ends,  one  of  which  was  opposite 
the  head  of  each  condyle  and  one  opposite  the  symphysis  of  the  chin. 
Each  of  the  three  ends  was  fitted  to  receive  a  tiny  lead  pencil.  A  hori- 
zontal plane  representing  the  occlusal  plane  was  affixed  to  the  wires 
to  facilitate  more  accurate  record  taking.  The  whole  appliance  was 
stable  in  position  and  made  all  the  movements  the  jaw  made.  The 
locations  of  the  pencils  and  occlusal  plane  are  shown  in  Figure  ^o.  91. 


RECORDING  OPENING  AND   CLOSING  MOVEMENTS. 


To  record  the  movements  of  the  condyles  and  chin  in  straight  open- 
ing and  closing,  a  frame  like  that  shown  in  Fig.  No.  92  was  held 
immovably  against  the  head,  and  the  pencils  recorded  upon  it  as  the 
jaw  moved.  The  pencil  and  arm  on  the  right  side  have  been  removed, 
to  permit  a  better  view  of  the  path,  but  their  location  is  shown  by  dotted 
lines.  The  chin  pencil  and  its  path  are  shown.  The  points  in  both 
paths  numbered  from  1  to  5  inclusive  are  known  as  "stations"  and 
indicate  that  when  the  pencil  recording  the  condyle  path  was  arrested  at 
any  given  point,  the  pencil  recording  the  chin  path  was  located  at  the 
point  of  like  number,  as  at  station  3  in  both  paths. 

It  will  be  noticed  that  the  chin  path  describes  a  loop.  This  is 
because  this  pencil  regularly  took  one  path  in  the  opening  movement 
and  another  in  the  closing  movement. 

The  importance  of  these  records  and  their  meaning  will  be  de- 
scribed after  the  method  of  recording  the  movements  in  the  horizontal 
plane  has  been  described. 

142 


Fig.  91. 


KiK.  '.IJ 


143 


THE  IMPOKTANCE  OF  THE  RECORDS  OF  THE  OPEl^IXG 
AKD  CLOSING  MOVEMENTS. 

They  establish  the  fact  that  these  movements  cannot  be  reproduced 
with  the  condyles  as  the  centers  of  movement. 

Only  the  portion  of  the  condyle  path  numbered  1-2  is  employed 
while  the  teeth  are  in  articulation,  and  the  teeth  pass  out  of  contact 
when  the  condyle  reaches  station  3. 

Records  of  condyle  and  chin  movements  made  in  the  manner 
described  on  page  142  were  transferred  to  flat  sheets,  and  a  common 
center  for  portions  1-2  of  the  condyle  path  and  portions  1-2  of  the  chin 
path  was  located  by  erecting  right  angles  from  each  path  and  prolonging 
them  until  they  met,  as  in  Figure  No.  93. 

This  center  is  located  vertically  about  half  way  between  the  level 
of  the  occlusal  plane  and  the  heads  of  the  condyles,  and  a  little  back 
of  the  condyle.  Patients  occasionally  present  with  the  rotation  points 
on  the  level  of  the  condyles  or  the  occlusal  plane,  but  they  are  greatly 
in  the  minority. 

The  mechanical  accuracy  of  such  a  location  can  be  easily  seen  by 
tracing  on  paper  the  outlines  of  Figs.  Nos.  94  and  95  and  perform- 
ing a  simple  experiment. 

Fig.  No.  94  shows  the  outline  of  a  mandible  with  the  correct 
average  paths  of  the  condyles  and  incisors.  Fig.  95  shows  an  out- 
line of  a  similar  mandible,  with  the  points  A-B-C  as  possible  rotation 
points.  A  is  the  rotation  point  common  to  all  articulators  where  the 
condyles  are  the  centers  of  motion.  C  is  located  on  the  level  of  the 
occlusal  plane.  B  is  the  point  determined  upon  by  erecting  perpendicu- 
lars on  the  portions  1-2  of  the  condyle  and  chin  paths  in  Fig.  93. 

If  Fig.  No.  93  be  superimposed  on  Fig.  No.  94  and  if  a  pin 
be  thrust  successively  through  the  points  A-B-C  and  the  mandible  be 
moved  vertically  across  the  outline  from  Fig.  94,  it  can  be  seen  that 
when  the  pin  is  at  the  point  A  there  are  no  correct  opening  and  closing 
movements  of  the  condyles.  The  lower  incisors  move  through  the  path 
A-2,  which  is  inclined  too  far  forward  as  it  goes  upward  and  too  far 
backward  as  it  goes  downward.  The  molars  move  very  much  too  far 
forward  and  backward  in  like  manner. 

When  the  pin  is  at  C,  the  condyle  describes  the  movement  indicated 
by  the  dotted  line  in  Fig.  95.  This  is  unlike  the  movement  of  the 
condyle  in  opening  and  closing.  The  incisors  move  through  the  line 
C-c,  which  inclines  too  far  forward  as  it  descends  and  too  far  backward 
as  it  goes  upward.  The  molars  move  in  like  manner  and  on  a  shorter 
curve. 

With  the  pin  at  B,  the  condyle  follows  very  closely  along  the  con- 
dyle path  in  Fig.  94,  while  the  incisors  move  through  the  path  B-b, 
which  reproduces  portion  1-2  of  the  incisor  path.  The  molars  move  in 
like  manner.  It  is  evident,  therefore,  that  if  an  articulator  is  to  cor- 
rectly reproduce  opening  and  closing  movements,  the  rotation  points 
must  be  in  the  vicinity  of  the  point  B. 

144 


Fig.   93 


Fig.   94. 


Fit:.  9.1 
145 


THE   PKACTICAL  IMPOKTANCE   OF   CORRECT   OPEIsTIKG 
A1«[D  CLOSING  MOVEMEI^TS. 

Wlien  the  rotation  points  of  the  articulator  are  in  correct  vertical 
locations,  it  is  not  quite  so  essential  that  the  models  be  mounted  on  the 
articulator  with  the  distance  from  condyles  to  incisors  exactly  like  the 
corresponding  distance  in  the  mouth.  The  bite  may  be  raised  or 
lowered  at  will,  either  by  design  or  accident,  without  deranging  the 
articulation  of  the  teeth. 

Both  of  these  points  are  of  great  importance.  If  it  be  noted  how 
much  too  far  forward  and  back  the  molar  path  "A"  passes,  in  Fig. 
No.  95,  page  145,  it  can  be  seen  that  if  the  models  be  mounted  too 
near  the  condyles  and  the  rotation  point  of  the  articulator  be  in  the 
location  of  ''A"  or  "C",  in  the  same  figure,  the  teeth  will  rapidly  pass 
into  wrong  relations  if  the  bite  be  raised  or  lowered. 

The  effect  of  raising  the  bite  when  the  rotation  point  of  the 
articulator  is  in  the  condyles,  is  diagrammatically  illustrated  in  Fig. 
No.  96.  When  the  teeth  are  placed  in  the  mouth  where,  in  all  proba- 
bility the  rotation  points  are  not  in  the  condyles,  the  molars  come  into 
contact  before  the  anterior  teeth.  Such  contact  either  thrusts  the  lower 
denture  forward  or  displaces  the  upper. 

Exactly  the  opposite  result  occurs  if  the  rotation  point  of  the 
articulator  is  on  the  level  of  the  occlusal  plane  and  the  bite  is  raised. 
The  front  teeth  then  come  into  contact  before  the  posteriors. 

Such  forms  of  wrong  contact  have  been  very  common  in  the  past 
because  dentists  could  not  determine  the  source  of  the  trouble.  They 
are  very  difficult  to  correct  by  grinding  the  teeth,  and  teeth  so  ground 
lose  all  their  power  of  efficient  mastication.  Moreover,  such  dentures 
require  repeated  grindings  to  keep  them  even  comfortable. 

When  the  rotation  points  of  the  articulator  are  located  at  about 
the  point  "B,"  the  bite  may  be  raised  or  lowered  as  desired  without 
deranging  the  articulation  when  the  teeth  are  put  into  the  mouth.  In 
one  test  case,  the  bite  was  closed  the  full  length  of  the  upper  centrals 
without  any  bad  effects. 

It  is  often  advantageous  to  be  able  to  arrange  the  teeth  for  a 
slightly  higher  bite  than  the  patient  recorded,  either  that  the  cheek 
tissues  may  be  stretched  and  wrinkles  taken  out,  or  for  esthetic  purposes. 
It  is  sometimes  desirable  to  set  the  teeth  a  little  high  and  close  them 
down  to  just  the  desired  position  when  they  are  tried  in  the  mouth. 

The  height  of  the  bite  is  often  changed  without  intention. 

Fig.  No.  97  shows  that  if  the  rotation  point  of  the  articulator 
is  at  the  location  "B,"  the  lower  teeth  move  through  such  lines  that 
the  cusps  of  one  set  will  articulate  with  the  grooves  of  the  other  set,  no 
matter  how  far  the  movement  may  be  carried. 

146 


Fig.   90. 

Schematic  illustration  of  the  effect  of  raising  the  bite  in  an  articulator  having  the 
rotation  points  in  the  condyles  "A." 

On  close  examination  it  is  seen  that  the  distal  slopes  of  the  lower  cusps  come  in 
contact  with  the  mesial  slopes  of  the  upper  cusps  long  before  the  other  slopes  antagonize. 
The  molars  strike  before  the  bicuspids  do.  This  is  not  articulation,  and  these  teeth 
cannot  be  ground  to  anything  more  than  the  crudest  form  of  articulation. 


Fig.  t'7. 

Scheniati',-  illustration  of  tlie  opposition  of  teeth  with  "B"  as  rotation  point.  The 
condyle  moves  through  its  normal  path.  The  cusps  f>f  the  lower  teeth  move  through 
lines  which   bring  them   into' proper  relations,  when   the  bite  is  raised  or  lowered. 


147 


KECOKDING  LATERAL  MOVEMENTS  OF  CONDYLES  AND 

CHIN. 

For  the  purpose  of  recording  the  movements  of  the  condyles  during 
lateral  movements  of  the  jaw,  the  points  of  the  pencils  opposite  the 
condyle  heads  were  turned  upward,  and  caused  to  register  on  a  frame 
supporting  pieces  of  ground  glass,  as  shown  in  Fig.  No.  98.  The 
pencil  at  the  symphysis  was  turned  with  the  Sagittal  plane,  and  recorded 
on  a  card  held  at  right  angles  with  that  plane. 

The  records  of  the  pencils  opposite  the  condyles  showed  that  the 
condyles  have  movements  which  were  practically  unknown  and  which 
had  not  been  incorporated  into  articulators.  The  condyle  on  the  "work- 
ing side"  moved  out  of  the  fossa,  away  from  the  median  line,  while  the 
advancing  condyle  moved  strongly  inward.  Measurements  of  the  move- 
ments of  other  jaws  showed  that  these  records  differed  in  degree  but 
not  in  character. 

It  is  not  unnatural  that  these  movements  should  be  present,  as  is 
seen  when  the  bony  formation  of  the  glenoid  fossae  and  condyles  is 
examined.  The  articulating  surfaces  of  the  fossae  face  inward,  some- 
times very  strongly,  as  is  shown  in  Fig.  No.  99.  The  portions  of  the 
condyles  engaged  in  articulation  during  the  lateral  movements  of  the 
j  aw,  faces  inward  in  the  same  degree.  It  is  natural  that  condyles  which 
face  inward  and  which  articulate  with  surfaces  that  face  inward,  should 
move  inward  as  they  move  forward.  The  records  of  a  large  number 
of  cases  show  that  the  advancing  condyle  moves  inward  at  an  average 
inclination  of  16  degrees  with  the  Sagittal  plane.  This  is  a  much 
stronger  inward  movement  than  would  be  exhibited  by  an  arc  of  a  circle 
with  the  other  condyle  as  a  center. 

The  records  of  the  pencil  at  the  symphysis  were  portions  of  curves. 
They  revealed  one  very  important  point  which  will  be  more  fully  con- 
sidered later,  namely,  that  they  were  not  arcs  of  circles  of  which  the 
condyles  were  the  centers. 


148 


Fig.  98. 


Vig.   <M. 

149 


THE  IMPOKTANCE  OF  THE  RECOKDS  OF  THE  LATERAL 

MOVEMENTS. 

The  records  of  the  lateral  movements  seem  to  me  more  important 
than  the  records  of  the  opening  and  closing  movements,  because  the 
lateral  movements  are  more  numerous  than  the  incising  movements,  and 
because  these  are  the  movements  which  usually  dislodge  dentures  which 
have  been  merely  occluded. 

The  records  show  that  the  condyles  are  rarely  if  ever  the  centers 
from  which  the  movements  have  been  produced,  and  that  they  cannot  be 
reproduced  by  articulators  having  the  rotation  points  in  the  condyles. 

These  records  show  also  that  the  location  of  the  rotation  points,  as 
to  distance  outward  from  the  median  line,  differs  greatly  in  different 
mouths,  and  sometimes  on  different  sides  of  the  same  mouth.  It  appears 
that  when  the  teeth  are  lost  irregularly,  the  horizontal  location  of  the 
rotation  point  changes  to  accommodate  changed  movements  in  nuisii- 
cation.  Sometimes  the  rotation  points  are  between  the  condyles  and 
the  median  line,  in  which  case  they  are  said  to  be  ''inside  the  condyles." 
Sometimes  they  are  farther  from  the  median  line  than  the  condyles,  in 
which  case  they  are  said  to  be  ''outside  the  condyles." 

These  records  help  us  to  understand  why  we  have  failed  in  articu- 
lating many  dentures  to  which  we  have  given  our  best  efforts.  If  we  had 
been  able  to  record  the  jaw  movements  in  such  cases,  we  should  doubt- 
less have  found  the  rotation  point  on  one  side  of  the  head  "inside  the 
condjde,"  and  the  rotation  point  on  the  other  side  "outside  the  condyle," 
and  that  the  articulator  on  which  we  arranged  the  teeth  could  not  be 
adjusted  to  such  locations,  and  could  not  correctly  reproduce  the  jaw 
movements. 

Figs.  jSTos.  100  and  101  illustrate  the  movements  of  two  extreme 
cases.  The  horizontal  location  of  the  rotation  points  is  determined  by 
the  same  method  employed  to  determine  the  vertical  location,  that  is 
by  erecting  perpendiculars  on  the  recorded  lateral  paths  of  the  condyles 
and  incisor  point.    The  locations  are  marked  Ro.  R.  and  Ro.  L. 

Fig.  102  illustrates  the  movements  in  a  case  where  the  position  of 
the  right  condyle  is  identical  with  that  in  Fig.  101  and  the  position 
of  the  left  condyle  is  identical  with  that  in  Fig.  100.  The  great 
difference  in  the  movements  on  the  opposite  sides  of  this  mouth  shows 
very  clearly  the  importance  of  locating  with  at  least  approximate 
accuracy  the  positions  of  the  condyles. 

150 


Fig-.   100 


THE  PRACTICAL  VALUE  OF  THE  LATERAL  MOVEMENTS. 

They  reduce  the  steepness  of  the  downward  path  of  the  condyle  as 
we  have  been  accustomed  to  record  it  on  articulators,  so  that  the  com- 
pensating and  lateral  curves  of  the  dentures  need  not  be  so  steep  as 
when  no  lateral  movements  are  present. 

They  permit  articulation  with  much  shallower  bites  in  the  molars 
than  would  be  necessary  were  no  lateral  moA'ements  present. 

They  change  the  articulation  of  the  posteriors. 

They  often  permit  the  lower  anteriors  to  be  set  to  deeper  under- 
bite  without  being  set  back  too  far. 

In  most  cases  they  greatly  increase  the  cutting  power  of  the  incisors. 

It  is  not  uncommon  for  condyles  to  register  a  downward  move- 
ment of  60  degrees  or  90  degrees  to  the  occlusal  plane,  when  the  lower 
jaw  is  thrust  forward  in  the  incising  bite.  When  the  combined  down- 
ward and  lateral  movements  are  recorded,  the  downward  inclina- 
tion is  rarely  more  than  50  degrees,  and  two-thirds  of  all  movements 
seem  to  fall  between  30  degrees  and  40  degrees  in  inclination. 

The  more  slightly  inclined  paths  make  it  possible  to  set  the  den- 
tures with  flatter  compensating  and  lateral  curves.  Dentures  with  flat 
curves  are  easier  for  the  dentist  to  articulate  and  are  less  likely  to  be 
dislodged  during  jaw  movements  than  those  with  steep  curves. 

In  Fig.  103,  Prof.  Gysi  has  charted  the  required  depth  of  bite 
in  first  molars  with  different  degrees  of  inclination  of  the  lateral  path. 
The  articulator  was  set  with  the  condyles  12.5  centimeters  apart,  the 
rotation  point  10  centimeters  apart,  and  the  incisor  guide  incline  at 
40  degrees.  The  inclination  of  the  downward  path  of  the  condyle  was 
at  first  fixed  at  20  degrees,  then  at  30  degrees  and  lastly  at  40  de- 
grees. The  lateral  path  was  at  first  given  no  inclination  and  the 
advancing  condyle  described  merely  the  arc  of  a  circle  about  the  rota- 
tion point  of  the  opposite  side.  Later,  it  was  given  inclinations  of 
10  degrees,  20  degrees  and  30  degrees. 

By  reading  directly  down  the  column  of  illustrations  under  the 
heading  "Con.  20  degrees,"  it  will  be  seen  that  the  depth  of  bite  in  the 
molars,  which  is  graphically  represented  by  the  figures  40  degrees,  125 
degrees,  15  degrees  when  there  is  no  definite  lateral  condyle  movement, 
grows  less  steep  as  the  lateral  inclination  of  the  condyle  path  increases, 
so  that  when  the  lateral  path  inclines  inward  30  degrees,  as  it  does  in 
some  cases,  the  depth  of  bite  is  represented  by  the  figures  18  degrees, 
157  degrees,  5  degrees.  The  vertical  lift  of  these  latter  teeth  in  articu- 
lation would.be  very  much  less  than  that  of  the  former. 

If  the  columns  under  the  headings  "Con.  30  degrees"  and  "Con. 
40  degrees"  be  studied  in  the  same  way,  it  will  be  seen  that  a  similar 
flattening  of  the  bite  occurs  as  the  inward  inclination  of  the  condyle 
path  becomes  more  pronounced. 

152 


FIRST    MOLAR 
COND.12.5  cm.  ROT.  FTS.  lOCm.    INCISOR  INCLUDE  40* 


-_^ 


Fig.    103. 


FIRST  MOLAR 

ROT.  PTS.IOCTTl.       INCISOR  INCLINE  40° 


Fig.   104. 


FIRST   MOLAR 
A0V.CONO.30MNW.  LAT.  INC.  10"  INCISOR  INC.40* 


ROT.  POINTS  5Cm.    ROT.  POINTS  14  cm. 


-po: 


Fig.    100. 


A 


BALANCING 
BITE 


Fig.    105, 


Fig.    ]07. 


153 


If  the  depth  of  bite  required  by  articulators  in  which  the  advancing 
condyle  moves  only  through  the  arc  of  a  circle  about  the  other  condyle 
is  represented  by  the  upper  figures  in  the  three  rows  here  shown,  and 
the  depth  of  bite  required  by  an  articulator  with  properly  located  rota- 
tion points  and  properly  inclined  lateral  paths  is  represented  by  the 
depth  shown  in  the  three  figures  in  which  the  lateral  path  is  inclined 
at  20  degrees,  it  appears  evident  that  properly  formed  teeth  can  be 
much  better  articulated  in  an  articulator  with  properly  inclined  lateral 
paths.  It  is  evident  also  that  dentures  with  such  teeth,  thus  arranged 
will  be  more  stable  in  the  mouth  during  mastication  than  teeth  shaped 
without  reference  to  the  lateral  paths  or  arranged  in  articulators  which 
make  no  provision  for  lateral  movements. 

If,  now,  the  diagrams  in  Fig.  'No.  103  be  read  across  from  left 
to  right,  the  relatively  slight  influence  of  the  downward  path  on  the 
depth  of  bite  in  bicuspids  and  molars  will  be  made  plain. 

When  there  is  no  definite  lateral  movement,  the  change  of  the 
inclination  of  the  downward  path  from  20  degrees  to  40  degrees, 
changes  the  depth  of  the  working  bite  only  1  degree,  from  15  degrees 
when  the  downward  path  is  at  20  degrees,  to  14  degrees  when  the 
downward  path  is  at  40  degrees.  When  the  lateral  path  is  at  10  de- 
grees, the  change  of  the  downward  path  from  20  degrees  to  40  degrees, 
effects  no  change  whatever  in  the  depth  of  bite.  When  the  lateral 
movement  is  at  20  degrees,  the  change  of  the  downward  path  from  20 
degrees  to  40  degrees  changes  the  depth  of  working  bite  only  1  degree. 
When  the  lateral  path  is  at  80  degrees,  the  change  of  the  downward 
path  from  20  degrees  to  40  degrees,  effects  no  change  whatever  in  the 
depth  of  working  bite. 

These  figures  seem  to  me  to  indicate  that  the  lateral  path  of  the 
condyles  exerts  more  eft'ect  on  the  articulation  of  the  bicuspids  and 
molars  than  does  the  downward  path.  It  is  partly  for  this  reason  that 
I  regard  the  lateral  path  as  more  important  in  an  articulator  than  the 
downward  path. 

Fig.  104  shows  the  depth  of  bite  required  when  the  advancing 
condyle  of  an  articulator  moves  straight  forward  without  describing 
even  an  arc  of  a  circle.  The  rotation  points  were  fixed  10  centimeters 
apart,  and  the  incisor  guide  incline  at  40  degrees.  In  the  columns  of 
diagrams  on  the  left,  the  condyles  were  fixed  15.5  centimeters  apart. 
In  the  column  on  the  right,  the  condyles  were  fixed  12.5  centimeters 
apart. 

The  diagrams  show  that  when  the  downward  condyle  path  is  in- 
clined 20  degrees,  the  depth  of  the  working  bite  is  18  degrees,  as 
against  8  degrees  when  the  path  of  the  combined  downward  and  in- 
ward condyle  movements  register  20  degrees.  When  the  advancing 
condyle  moves  straight  forward  at  a  downward  inclination  of  40  de- 
grees, the  depth  of  the  working  bite  is  20  degrees,  as  compared  with 
5  degrees,  7  degrees,  or  10  degrees,  when  the  combined  downward 
and  inward  movement  registers  40  degrees.  This  is  another  evidence 
of  the  influence  of  the  lateral  path  of  the  condyle  on  the  depth  of  bite. 

154 


Fisr.  lOS 


The  dentures  here  shown  are  ilhistrations  of  the  difficulties  often 
encountered  in  articulating  teeth  without  adequate  records. 

A  dentist  of  no  mean  skill  made  for  the  patient  full  upper  and 
lower  dentures  using  the  articulator  which  had  been  most  highly  re- 
garded up  to  the  time  of  the  discovery  of  the  rotation  points  and  lateral 
paths.  By  painstaking  care  he  had  secured  excellent  articulation  of  the 
dentures  on  the  left  side  of  the  mouth,  but  had  been  unable  to  articulate 
the  teeth  on  the  right  side  to  be  efficient  in  mastication,  though  they 
balanced  the  dentures  pretty  well.  Efforts  to  arrange  the  teeth  in  the 
mouth  had  been  unsuccessful. 

When  the  condyle  paths  were  recorded  by  Prof.  Gysi's  methods,  it 
was  found  that  the  downward  path  differed  as  follows :  on  the  two  sides, 
that  the  lateral  paths  of  the  condyle  differed  also,  and  that^  the  lateral 
patli  of  the  incisor  point  was  so  different  on  the  two  sides  of  the  mouth 
as  to  require  that  one  rotation  point  be  located  as  far  outward  horizon- 
tally, as  the  condyle,  while  the  other  was  less  than  half  as  far  outward 
from  the  median  line. 

Here,  then,  was  a  mouth  in  which  the  movements  of  the  two  sides 
differed  in  every  important  particular.  It  is  not  wonderful  that  teeth 
could  not  be  arranged  for  such  conditions  in  an  articulator  which  em- 
ployed the  condyles  as  fixed  rotation  points  and  in  which  the  lateral 
paths  of  the  condyles  and  incisors  could  not  l)e  correctly  reproduced. 

When  the  movements  peculiar  to  this  nioufh  had  been  reproduced 
in  an  articulator,  the  teeth  were  arranged,  and  when  tried. in  for  the 
first  time,  articulated  perfectly  on  both  sides  of  the  mouth. 

155 


THE  PRACTICAL  VALUE  OF  THE  LATERAL  MOVEMENTS, 

(Continued.) 

These  figures  show  that  the  downward  path  of  the  condyle  has 
relatively  slight  influence  on  the  formation  of  the  teeth  and  depth  of 
bite,  for  a  difference  of  20  degrees  in  the  inclination  of  the  straight 
forward  and  downward  movement  changes  the  depth  of  the  bite  only 
2  degrees. 

Fig.  104  should  be  interesting  to  those  dentists  who  have  desired 
articulators  with  the  condyles  adjustable  for  different  distances  from 
the  median  line.  The  vertical  column  on  the  left  shows  records  from 
an  articulator  with  the  condyles  set  at  a  width  of  15.5  centimeters, 
while  the  column  on  the  right  shows  similar  records  with  the  condyles 
set  12.5  centimeters  apart.  It  will  be  noticed  that  the  difl'erence  in 
the  distance  of  separation  has  made  no  change  in  the  working  bite, 
and  has  only  rendered  the  working  bite  slightly  steeper  for  the  more 
widely  separated  condyles.  It  is  quite  possible  that  dentists  who  have 
expressed  wishes  for  articulators  with  adjustable  condyles  have  in 
reality  desired  articulators  with  adjustable  rotation  points. 

Fig.  105  shows  that  considerable  changes  in  depth  of  wo^'khig 
bite  result  from  wide  differences  in  the  horizontal  positions  of  the 
condyles.  If  the  rotation  points  be  close  to  the  median  line,  only  5  centi- 
meters apart,  the  working  bite  will  have  an  inclination  of  only  3  de- 
grees, when  the  downward  path  is  inclined  30  degrees,  the  lateral 
path  10  degrees,  and  the  incisor  path  40  degrees.  If,  however,  the 
rotation  points  be  moved  until  they  are  14  centimeters  apart  in  the 
same  horizontal  plane,  the  working  bite  will  have  a  depth  of  14  de- 
grees, while  the  lingual  cusps  of  the  molars  will  have  quite  a  different 
buccal  slope.  The  average  distance  between  the  rotation  points  is  10 
centimeters.  It  is  evident,  therefore,  that  the  horizontal  distance  be- 
tween the  rotation  points  is  much  more  important  than  the  horizontal 
distance  between  the  condyles. 

The  vertical  inclination  of  the  incisor  path  has  more  influence 
on  the  forms  of  the  teeth  and  the  ease  of  articulation,  than  has  the 
downward  movement  of  the  condyle  path.  Fig.  106  shows  the 
forms  of  first  molars  necessary  with  different  vertical  inclinations  of 
the  incisor  path.  The  condyles  were  fixed  at  12.5  centimeters  apart, 
the  rotation  points  at  10  centimeters,  the  downward  path  of  the  con- 
dyle at  30  degrees,  and  the  lateral  inclination  of  the  advancing  condyle 
path  at  15  degrees.  In  the  upper  diagram  the  incisor  path  inclines 
vertically  at  20  degrees.  The  depth  of  the  working  bite  is  10  degrees 
and  the  buccal  incline  of  the  upper  lingual  cusp  is  fixed  at  20  degrees. 
The  inclination  of  the  incisor  path  was  then  changed  to  60  degrees, 
which  is  approximately  what  it  is  in  the  natural  teeth  at  the  period 
of  greatest  efficiency.  The  depth  of  the  working  bite  is  increased  to 
18  degrees  and  the  inclination  of  the  buccal  incline  of  the  upper 
lingual  cusp  becomes  much  steeper.  Prof.  Gysi  believes  that  an  inclina- 
tion of  40. degrees  for  the  incisor  incline  is  better  in  prosthetic  work 
than  the  steep  inclination  of  that  incline  in  the  natural  teeth.  ^ 

156 


Fig.   109. 

These  diagrams  seem  to  show  that  the  steepness  of  the  vertical  in- 
clination of  the  incisor  path  has  more  inilnence  on  the  depth  of  bite 
in  the  incisors,  bicnspids  and  first  molars,  than  has  the  vertical  inclina- 
tion of  the  condyle  path,  bnt  that  the  influence  of  the  condyle  path 
govern.s  the  positions  of  the  second  molars. 

Fig.  No.  109 A  shows  at  the  bottom  an  incisor  guide  incline, 
with  a  vertical  inclination  of  20  degrees  to  the  occlusal  plane.  At  the 
top  is  a  diagram  of  a  downward  condyle  path  inclined  45  degrees.  Just 
above  the  incisor  guide  is  shown  the  position  of  the  first  molars  re- 
quired by  these  inclinations  of  incisor  and  condyle  paths.  The  position 
of  the  second  molars  is  shown  above  that  of  the  first  molar. 

Fig.  No.  109B  shows  at  the  bottom  an  incisor  guide  incline  with  a 
vertical  inclination  of  40  degrees,  and  aftop  a  diagram  of  a  downward 
condyle  path  inclined  20  degrees.  The  position  of  the  first  molars  re- 
quired l)y  these  inclinations  is  shown  just  above  the  incisor  incline,  and 
the  position  of  the  second  molars  just  above  the  first. 

It  will  be  noted  that  the  incisor  path  which  is  vertically  inclined 
40  degrees  has  deepened  the  -working  and  balancing  bites  in  the  first 
molar,  as  compared  with  those  in  Fig.  A  where  the  incisor  path  inclines 
verticallv  onlv  lialf  as  much.  It  will  be  seen  that  in  the  second  molars 
the  balancing  bite  is  deeper  in  Fig.  A,  where  the  condyle  path  is  more 
stecplv  inclined.  t       • 

tho.se  facts  seem  to  bo  evidence  that  the  very  steep  inclinations  of 
the  coiidvlo  path  frecpunitly  obtained  by  means  of  the  incising  bite, 
merely  result  in  arranging  dentures  to  very  steep  lateral  and  compen- 
sating curves  in  the  second  molars,  whereas  the  less  steeply  inclined 
paths  recorded  by  Dr.  Gysi's  methods,  especially  when  aided  by  correct 
incisor  supports,"  result  in  the  arrangement  of  dentures  to  flatter  curves, 
witli  incroasofl  stability. 


157 


THE    I^FLUEXCE    OF    THESE    ADJUSTME^sTTS    O:^    THE 
MOVEMEA'TS  OF  THE  BICUSPIDS  A^D  MOLAES. 

The  adjustments  of  tlie  downward  condyle  path,  the  inward 
lateral  path,  the  vertical  incisor  path  and  the  distance  between  the 
rotation  points  affect  the  movements  of  the  teeth,  107  A  B  C  D. 

In  Fig.  107A,  the  effect  on  molar  movements  in  balancing  bite 
of  three  locations  of  the  rotation  points  in  the  same  horizontal  plane  are 
shown  in  the  three  lines  marked  "R.5  cm.,"  which  indicates  a  separation 
of  5  centimeters  between  the  rotation  points,  the  lines  marked  "10  cm.," 
which  indicates  a  separation  of  10  centimeters,  and  the  lines  marked 
"14  cm."  which  indicate  a  separation  of  14  centimeters. 

The  influence  of  the  several  inclinations  of  the  downward  path 
of  the  condyle  is  confined  to  the  balancing  bite,  as  is  shown  in  Fig. 
107B.  The  line  marked  "C20  degrees,"  indicates  the  movement  of 
the  teeth  when  all  the  other  adjustments  are  average  and  the  advanc- 
ing condyle  path  inclines  downward  20  degrees.  The  line  marked 
"C  30  degrees"  indicates  the  movements  of  the  teeth  when  the  other 
adjustments  are  unchanged  but  the  advancing  condyle  path  inclines 
downward  30  degrees.  The  inclination  of  the  line  marked  "C  40 
degrees"  indicates  the  movements  of  the  teeth  when  the  adjustments 
are  as  above  except  that  the  advancing  condyle  path  inclines  downward 
40  degrees.  It  will  be  noticed  that  in  the  working  bite  the  move- 
ments of  the  teeth  are  identical  in  all  three  of  these  inclinations. 

In  Fig.  107C  the  influence  of  the  lateral  inclination  of  the 
advancing  condyle  movement  is  shown.  The  line  marked  "L  0  degrees" 
is  the  path  taken  by  the  teeth  when  the  downward  path  of  the  condyle 
is  inclined  33  degrees,  the  vertical  incisor  path  40  degrees,  and  the 
advancing  condyle  moves  forward  only  through  the  arc  of  a  circle  with 
the  other  condyle  as  the  center.  The  lines  marked  "L  30  degrees," 
indicate  the  movements  of  the  teeth  when  the  other  adjustments  of  the 
articulator  are  as  mentioned,  but  the  rotation  points  are  so  adjusted  that 
the  advancing  condyle  path  inclines  inward  30  degrees. 

Fig.  107D  shows  two  lower  molar  teeth  with  three  lines  drawn 
to  lingual  and  three  to  buccal.  The  anterior  and  posterior  lines  in  each 
group  of  three,  indicate  the  extreme  difference  in  direction  and  extent 
of  tooth  movement  as  affected  by  the  adjustments  in  Fios.  107 
A-B-C. 

The  middle  line  in  each  group  of  three  represents  the  medium 
course  between  these  extremes  of  movement.  It  is  secured  by  a  medium 
adjustment  of  an  articulator,  so  that  the  rotation  points  are  10  centi- 
meters apart,  the  advancing  condyle  path  inclines  downward  at  about 
33  degrees  and  inward  at  about  16  degrees,  and  tlie  incisor  path 
inclines  vertically  at  40  degrees. 

Prof.  Grysi  believes  that  such  adjustments  will  meet  the  require- 
ments of  about  two-thirds  of  all  cases. 

158 


PERMIT  DEEPER  UXDERBITE  OF  LOWER  TXCISORS. 

The  lower  incisors  should  generally  be  set  far  enough  back  of 
the  upper  incisors  so  that  thej  are  just  out  of  contact  with  the  uppers 
when  the  jaw  is  at  rest  in  central  occlusion.  The  depth  of  underbite 
to  which  they  mav  be  set,  when  in  this  position,  is  determined  hy  the 
degree  in  which  they  move  forward  across  the  upper  incisors,  as  the 
jaw  moves  laterally.  The  more  strongly  forward  they  move,  the  less 
may  be  the  depth  of  underbite.  The  more  sideways  they  move,  the 
deeper  may  be  the  underbite. 

The  degree  of  forward  movement  of  the  incisors,  in  lateral  move- 
ments of  the  jaw,  is  determined  by  the  horizontal  location  of  the  rota- 
tion points.  If  the  rotation  points  are  located  well  inside  the  con- 
dyles, the  incisors  will  pass  strongly  sideways,  and  may  be  set  to  a 
relatively  deep  underbite.  If  the  rotation  points  are  located  at  the 
condyles,  the  movement  will  be  rather  strongly  forward,  and  the  lower 
incisors  can  usually  be  set  to  only  a  very  shallow  underbite.  If  the 
rotation  points  are  outside  the  condyles,  the  underbite  will  l)e  extremely 
shallow.  If  one  rotation  point  is  inside  the  condyle  and  one  outside, 
the  depth  of  underl)ite  will  vary  on  different  sides  of  the  median  line. 

The  movements  of  the  incisors  which  determine  the  depth  of 
underbite  possible  in  these  three  conditions  can  be  better  understood 
by  a  study  of  the  incisor  movements  in  Figs.  100,  101,  10:2. 

The  average  locations  of  the  rotation  points  are  one  centimeter 
inside  each  condyle.  That  is,  if  the  condyles  are  four  inches  apart,  on 
the  average,  the  rotation  points  would  be  a  little  over  three  inches  apart. 
This  position  permits  the  articulator  to  reproduce  the  average  lateral 
inclination  of  the  condyle  paths  and  of  the  incisor  path.  With  the 
rotation  points  in  this  location,  the  lower  incisors  pass  sideways  and 
forward  in  a  path  which  permits  setting  them  to  a  deeper  underbite 
than  when  the  rotation  points  are  as  far  from  the  median  line  as  the 
condyles.  The  artistic  effect  of  the  deeper  underbite  is  pleasing,  and 
the  more  strongly  inclined  sideways  path  of  the  lower  incisors  seems 
less  likely  to  dislodge  the  dentures. 

INCREASE  THE  CUTTIXG  POWER  OF  THE  IXCISORS. 

The  cutting  power  of  the  incisor  teeth  is  determined  not  alone 
by  the  forms  of  the  teeth  and  the  power  of  the  jaw,  but  in  no  small 
degree  by  the  direction  of  the  movement  by  which  the  lower  incisors 
cross  the  uppers.  The  more  directly  the  lower  incisors  move  across 
the  uppers,  the  less  the  cutting  power.  The  more  the  lower  incisors 
move  sideways  in  moving  across  the  uppers,  the  greater  the  cutting 
power.  This  is  often  important  in  artificial  dentures,  where  patients 
freqviently  require  the  maximum  cutting  power  possible. 

The  relative  cutting  powers  of  the  straight  forward  movement 
and  the  strong  lateral  movement  are  diagranimaticallv  shown  in  b'igs. 
Xos.  110-11-12-13. 

159 


Fig.    110. 
Upper  and  lower  teeth  set  to  only  straight  up  and  down  movement  may  be  diagram- 
matically  illnstrated   by   the   two   wedges   here   shown.     It   requires   much   force   to   push 
them  through  the  food,   shown  as  F. 


Fig.   111. 


The  sideways  movement  of  the  teeth  may 
be  here  diagrammatically  represented  by 
two  wedges  and  the  food  by  the  round  body 
between  them.  If  the  wedges  are  forced 
vertically  through,  great  pressure  will  be 
required. 

If  the  wedges  be  moved  in  the  direction 
shown  by  the  arrows,  very  much  less  force 
will  be  "required.  The  reason  is  that  the 
cutting  form  of  the  wedges  is  changed. 
With  this  motion  the  form  of  the  wedge 
is  not  the  triangle  formed  by  the  lines 
A  D  E,  but  the  much  sharper  triangle 
which  is  drawn  inside  each  triangle  and 
lettered  A — A^ — A^  in  the  upper,  and  B — 
B^ — B2  in   the  lower. 


Fig.  112. 
The  dotted  outlines  reproduce  the  tri- 
angles A— D— E  and  B— D— E,  while  the 
solid  outlines  a — a^ — a^  and  b — b^ — b^  repro- 
duce the  triangles  A— A^^— A-  and  B— B^ — B^ 
which  were  produced  by  the  lateral  move- 
ment of  the  triangles  in  Figure  No.  111. 
The  sharper  triangles  have  about  three 
times  the  cutting  power  of  the  triangles 
A— D— E  and  B— D— E. 


Fig.   113. 
The  left  lower  incisor  at  "a"  is  in  the  position  of  articulation  with  the  upper  right 
central.     In   cases  with   strong   lateral   inclination   of  the   incisor   path,   it    will   return   to 
occlusion,  at  "b"  by  following  the  direction   of  the  arrow.     This  path  of  return  permits 
a  relatively   deep  underbite  and   great  cutting   poM'er. 


160 


THE  (;VSI   ADAPTABLE  ARTICULATOR. 
Eigs.  Xos.  114  and  115. 

There  niav  lie  several  articulators  wliicii  enable  the  dentist  to 
record  and  reproduce  the  luovemeuts  of  the  human  mandible,  but  I 
am  familiar  with  only  one — the  Gysi  Adaptable  Articulator. 

The  recording  instruments  which  accompany  this  articulator  per- 
mit the  dentist  to  record  the  downward  and  lateral  paths  of  the  condyles 
and  the  horizontal  path  of  the  incisor  point.  The  glenoid  fossa?  of  the 
articulator  are  so  arranged  that  the  inward  inclination  of  the  lateral 
path  of  the  advancing  condyle,  and  the  downward  path  can  both 
be  reproduced.  By  means  of  the  pattern  which  is  traced  on  the  Horse- 
shoe riate,  the  horizontal  location  uf  the  rotation  points  is  easily  deter- 
mined. 

'Ihis  articiilainr  ntfers  a  very  important  improvement  over  others 
in  an  Incisor  Gtiide  Jncline  on  the  lower  nujdel  bow  and  a  pin  attached 
to  the  upper  model  bow  which  travels  on  the  incline.  This  pin  supports 
the  anteridr  ])art  of  ihc  upper  model  bow  during  lateral  movements  of 
the  mandible.  This  support  is  important  to  correct  movements  of  the 
iucisor  point  and.  as  shown  on  page  157,  the  vertical  inclination  of  the 
horizontal  path  of  the  incisors  exercises  a  good  deal  of  influence  on  the 
positions  of  the  teeth  as  far  back  as  the  first  molar. 

The  vertical  inclination  of  this  path  on  the  articulator  is  mtich 
less  than  in  the  natural  teeth,  because,  as  Prof.  Gysi  has  re})eatedly 
pointed  our,  the  construction  of  artificial  dentures  is  an  engineering 
problem,  and  should  be  executed  in  that  manner  which  seems  to  promise 
the  greatest  degree  of  success  under  the  working  conditions.  The  In- 
cisor (iuide  Incline  slopes  vertically  at  an  angle  of  40  degrees  to  the 
occlusal  plane.  Put  the  Jncisor  Guide  Pin  moves  diagonally  across  it, 
and  the  actual  vertical  inclination  of  its  path  is  only  23  degrees. 

When  the  movements  peculiar  to  the  patient  have  been  reproduced, 
the  teeth  may  be  as  easily  arranged  as  on  any  other  articulator. 

I'he  technic  of  using  this  articulator  is  not  difficult  after  one  under- 
stands the  succession  of  steps  and  how  to  perform  them.  I  believe  it  a 
conservative  statement  that  this  articulator  demands  not  more  than  one 
hour  additional  time  in  the  beginning  of  a  case  and  less  time  in  the  final 
adaptation  of  a  case  than  any  other  articulator  with  which  I  am  familiar. 

If  one  were  to  take  50  full  denture  cases  and  agree  to  make  them 
comfortable  and  efficient  for  the  patients,  I  believe  it  could  be  done  in 
less  time  with  this  articulator  than  with  even  a  ])lain  line,  because 
teeth  ai-ranged  on  this  articulator  rarely  re(|uiic  any  cluiuges  when 
tried  in  the  mouth. 

'J'he  service  which  this  articulator  makes  possible  to  patients  en- 
titles the  dentist  to  a  higher  fee  than  dentures  made  on  other  ;irl  iculators 
because  they  cost  more  in  time  and  money  and  are  of  greater  \alue.  The 
service  is  really  cheaper  to  the  patient  at  the  advanced  fee,  because  the 
irnpi'oved  comfort  and  efficiency  of  tlie  dentui-es  ai'c  of"  gi-eiiter  worth 
to  the  patient's  health. 

161 


Pig.  114. 
The  articulating  frame   without   measuring  instruuieuti^ 


Fig.  115. 

The  parts  of  the  Gysi  Adaptable  Articulator  are  as  follows : 

Nos.  1-2,  upper  and  lower  parts  of  articulator  frame  which  carry  the  uuuer  and  lower 
model  bows. 

Nos.  lA  and  2A,  upper  and  lower  model  bows. 

Nos.  3-3  Straight  Incisor  Guide  Pin  and  Curved  Incisor  Guide  Pin.  The  curved  pla 
is  used  only  when  mounting  models  or  setting  anteriors. 

No.  3A  Small  pin  for  all  set  screws. 

Nos.  4-4  Frame  work   of   Condyle   Path    Register. 

Nos.  4A-4A  Pencil  holders  and  pencils  of  Condyle  Path  Register. 

Nos.  5-5  Lateral  Path  Register. 

Nos.  6-6A  Stand  and  gooseneck  for  holding  Condyle  Path  Register  and  models. 

No.  7   Horseshoe    plate. 

No.  8  Degree  plate  for  measuring  inclinations  of  paths. 

No.  9   Incisor   Path   Register. 

162 


THE  GYSI  SIMPLEX  ARTlCl'LATOU. 
Fig.  Xo.  110. 

Soon  after  Prof.  Gysi  had  perfected  the  (ivsi  Adaptable  Articiihi- 
tor  aud  its  advantages  became  apparent,  he  was  earnestly  besonght  by 
many  members  of  the  dental  profession  to  devise  an  articulator  which 
should  embody  the  principles  of  the  Adaptable,  but  which  did  not  re- 
quire measurements  on  the  patient  and  adjustments  according  to  those 
measurements. 

Prof.  Gysi  therefore  perfected  the  Gysi  Simplex,  fixing  the  rela- 
tions by  the  average  inclinations  of  several  hundred  condyle  and  incisor 
paths  which  he  had  recorded  by  means  of  the  Adaptable  Articulator. 

He  employed  the  same  form  of  condyle  and  fossa,  but  tixed  the  in- 
clination of  the  downward  path  at  oo  degrees  and  the  lateral  inclination 
of  the  advancing  condyle  path  at  10  degrees.  The  rotation  points  were 
fixed  half  way  between  the  heads  of  the  condyles  and  the  occlusal  plane, 
and  ten  centimeters  apart.  The  same  form  of  Incisor  Guide  Incline  and 
Incisor  Guide  Pin  w^as  employed.  An  Incisor  Guide  was  placed  on  the 
Incisor  Guide  Pin  so  that  if  the  dentist  did  not  wish  to  employ  a  face 
bow  for  determining  the  relations  of  the  models  to  the  condyles,  he  could 
fix  them  upon  the  basis  of  the  four  inch  triangle  suggested  l)y  Dr. 
Eonwill. 

I  have  now  been  familiar  with  this  articulator  for  about  two  years 
and  I  have  no  hestitation  in  saying  that  in  my  opinion  no  other  simple 
articulator  approaches  it  in  facilitating  arrangement  of  the  teeth  in 
harmony  with  correct  mandibular  movements.  If  the  inclination  of  the 
condyle  paths  and  incisor  paths  and  the  horizontal  location  of  the  rota- 
tion points  are  not  to  be  determined  for  each  patient  by  accurate  methods, 
it  is  better  to  employ  the  average  of  a  large  numl)er  of  locations  and  ii> 
cl illations  determined  by  correct  methods,  than  to  employ  methods  which 
are  inadequate  or  incorrect  for  determining  tlu^n  in  the  individual  case. 

Prof.  Gysi  is  of  the  opinion  that  this  articuhitor  meets  the  require- 
ments of  about  two-thirds  of  the  cases  as  they  present,  tiiough  of  course 
it  does  not  indicate  which  are  the  unusual  cases. 

A  clever  .Kmcrican  dentist  has  dex-ised  a  met  bod  which  I  l)elieve 
lariicly  increases  the  usefulness  of  tliis  articulator.  He  sets  the  u])per 
teetli  first  and  waxes  them  firmly  in  ])osition.  When  lie  sets  tlie  lower 
teeth  on  the  ridge,  he  places  the  pins  of  each  lower  tooth  on  a  cone  of 
liard  wax  and  then  surrounds  the  tooth  with  a  softer  wax.  After  articu- 
lating the  teeth  out  of  the  mouth,  he  puts  the  upper  and  lower  trial  den- 
tures, in  wax,  into  the  mouth  and  causes  the  patient  to  make  gentle 
lateral  movements  of  t,he  mandible  with  the  iippei-  and  lower  teeth  in  con- 
tact. If  this  is  carefully  done,  the  lower  teeth  are  rotated  upon  the 
cones  of  hard  wax  by  the  action  of  the  uppers  until  thv.y  assume  those 
positions  which  are  most  harmf)nious  with  the  ])ati(!nt's  jaw  movements. 
He  reports  very  satisfiictory  results. 

163 


INCISOR 
GUIDE   PIN 


ANATOMICAL 
GLENOID  FOSSA 

1^ 


ANATOMICAL 
CONDYLE 


GUIDE  INCLINE 


Fig.  116. 

The   Gysi   Simplex   Articulator    Open. 

The  Gysi  Simplex  Articulator  open  showing  some  of  the  improvements  which  are 
important  to  all  plate  workers.  The  condyles  are  formed  by  upright  steel  pins  working 
in  properly  formed  glenoid  f.ossse  which  direct  them  downward  at  an  inclination  of  33 
degrees  and  inward  at  an  inclination  of  16  degrees.  The  weight  of  the  upper  model  bow 
is  carried  on  the  Rotation  Points,  shown  in  Fig.  No.  117.  The  Incisor  Guide  Incline 
and  Incisor  Guide  Pin  secure  for  the  anterior  part  of  the  upper  model  bow  a  more 
accurate  movement  than  can  be  had  when  this  form  of  support  is  lacking. 


164 


UPPER    BOW 
SET    SCREWS 


SPRING  HOLDING 
PARTS   IN    POSITION 


Fig.    117. 

Rear   View   Gysi    Simplex   Artiriilator. 

The  vertical  location  of  tlie  rotation  points  half  wa.v  between  the  heads  of  the 
condyles  and  the  level  of  the  occlusal  plane  is  here  clearly  shown.  This  location  permits 
the  artificial  mandible  to  perform  correct  openiii.c  and  closing  movements,  so  that  the 
height  of  the  bite  may  be  altei-ed   without  deranging  the  articulation. 

The  horizontal  locution  of  the  rotation  points,  each  one  centimeter  inside  the  condyle, 
is  shown.  This  location  is  important  l)ecauso  it  permits  the  advancing  condyle  to 
describe  an  inward  lateral  movement  of  1(5  degrees,  and  the  other  condyle  to  move  out  of 
the  fossa  in  the  way  the  natural  condyle  does.  In  other  words,  it  permits  the  entire 
mandible  to  shift  to  tlie  side  in  close  imitation   of  the  shifting  of  the   natural   mandible. 

This  horizontal  location  of  the  rotation  points  also  imparts  to  tlic  incisor  point 
a  more  strongly  lateral  movement  than  occurs  when  the  rotation  points  are  at  the 
condyles.  T'his  location  permits  a  deejier  underbite  of  the  lower  anteriors  and  increases 
the  biting  power  of  the  teeth. 

The   Incisor  Cuide  is  not    shown   in   tliis  illustration   but    is   shown   in    Fig.   110. 


165 


PART  VI. 


Mounting  The  Trial  Plates 
On  The  Articulator 


MEASURIXG  THE  PATIEXT\S  .MAXDI  lU-LAK  .MOVEMENTS. 
Fies.  Xos.  llS-llU-l-2()-l-21-l-2-2-l-2:]'l-2^. 


'&" 


If  the  Horseshoe  Phite  was  applied  to  the  lower  trial  plate  and 
the  Hicisor  Path  Register  was  mounted  on  the  upper  trial  plate  in  the 
process  of  taking  the  bite,  and  the  horizontal  path  of  the  incisor  point  of 
the  upper  jaw  was  registered  as  described  on  page  43,  the  taking  of  the 
other  records  of  the  patient's  mandibular  movements  is  very  simple. 

If  the  Horseshoe  Plate  was  not  attached  to  the  lower  trial  plate  at 
that  time,  it  should  be  now.  Before  putting  it  into  position,  the  portion 
of  its  occlusal  surface  anterior  to  the  first  indentation  on  each  side  is 
blackened  hy  smoke  from  burning  oil  of  cloves  or  vaseline  on  cotton,  and 
a  thin  him  of  wax  is  spread  over  the  blackened  area  with  a  hot  spatula 
to  make  a  place  for  a  permanent  record,  or  the  plate  may  be  coated  with 
wax  mixed  with  lampl)l:ick.  The  lower  surface  of  the  Horseshoe  Plate 
is  then  pressed  ujxiii  the  occlusal  surface  of  the  lower  trial  plate  so  that 
the  blackened  area  pi'ojects  forward  of  the  anterior  margin  of  the  lower 
trial  plate,  and  that  the  whole  Horseshoe  Plate  is  evenly  placed  on  the 
two  sides  of  the  median  line  of  the  trial  plate,  with  the  two  bars  project- 
ing forward  in  that  line,  as  shown  in  Eig.  Xo.  118,  Any  elevations  in 
the  upper  trial  plate  caused  by  pressure  of  the  Horseshoe  Plate  should 
be  trimmed  away  and  a  little  vaseliuo  rubbed  on  the  Horseshoe  Plate 
to  facilitate  movements. 

The  Incisor  Path  Register  is  mounted  on  the  labial  surface  of  the 
upper  trial  plate  in  such  manner  that  the  recording  pin  is  over  the 
median  line,  and  that  when  the  pin  is  all  the  way  down  it  will  press  on 
the  blackened  area  of  the  Horseshoe  Plate,  The  position  of  this  pin  is 
controlled  by  a  spring  and  a  handle,  and  when  not  in  use  it  should  be 
lifted  and  turned  so  that  the  point  does  not  rest  on  the  Horseshoe  Plate. 

The  heads  of  the  condyles  are  located,  either  by  feeling,  or  by 
measuring  one-hall'  inch  forward  from  the  tragus  of  the  ear,  on  a  line 
toward  the  outer  corner  of  the  eye.  The  location  of  the  head  of  each 
condyle  is  plainly  marked  on  the  face. 

Place  both  trial  plates  in  the  mouth. 

The  Condyle  Path  Register  is  placed  in  position  by  mounting  it  on 
the  two  bars  projecting  forward  from  the  Horseshoe  Plate  as  shown  in 
Fig.  110. 

The  pencil  holders  at  the  rear  terminations  of  the  Condyle  Path 
Register  are  turned  so  that  the  ends  of  the  pencils  which  point  vertically 
are  al)0ut  one-half  inch  from  the  sides  of  the  face  and  opposite  the  marks 
locating  the  heads  of  the  condyles.  They  are  locked  in  those  positions. 
See  Fig.  119, 

The  patient  is  retjuested  to  move  the  mandible  fi'oni  side  to  side, 
keeping  it  in  contact  with  the  upper  jaw.  Some  patients  tind  it  difhcult 
to  do  this,  and  it  is  often  necessary  to  instruct  ])atients  l)v  standing  in 
front  of  them  and  performing  similar  movements  until  they  learn  how. 
Patients  who  have  worn  occluded  or  poorly  articulated  dentures  for  long 
periods  often  lose  all  control  of  the  jaw  movements,  and  in  some  cases 

169 


is  is  quite  impossible  to  make  records  of  deiinite  movements.     In  such 
cases  the  articulator  should  be  set  at  average  adjustments. 

The  frame  supporting  the  glass  or  celluloid  tabs  and  called  the 
Lateral  Path  Register,  is  held  about  the  head  in  the  manner  shown  in 
Figs,  ISTo.  119  and  120,  and  so  that  the  tabs  are  in  contact  with  the  ends 
of  the  vertical  pencils.  The  frame  is  held  at  an  inclination  of  about 
40  degrees  to  the  occlusal  plane,  and  firmlj  supported  in  position  by 
pressing  the  fingers  on  the  sides  of  the  head.  It  need  not  necessarily  be 
held  exactly  straight  front  and  back.  As  the  pencils  move,  it  can  be 
noted  whether  the  Register  is  so  inclined  that  the  pencils  continue  con- 
tact with  it,  and  it  should  be  inclined  until  the  pencils  maintain  contact 
with  it  throughout  the  movement. 

One  lateral  path  may  be  recorded  at  a  time,  but  it  is  then  necessary 
to  hold  the  Register  so  that  when  the  pencil  records  the  second  lateral 
path,  the  pencil  which  recorded  the  first  one  is  at  the  rear  termination 
of  the  path.  The  Register  must  be  held  in  the  same  front  and  back  axis 
during  the  making  of  both  records. 

The  dentist  should  not  be  discouraged  if  his  first  or  second  efforts 
do  not  afford  the  character  of  records  he  desires.  Some  patients  are  in- 
capable of  making  them  for  reasons  explained  above  or  because  of  defects 
in  the  articulating  mechanism.  One  patient  who  gave  trouble  in  this 
respect  was  found  to  have  sustained  an  injury  to  the  joint  thirty  years 
before,  which  greatly  limited  its  movement.  There  is  also  a  slight 
technic,  as  there  is  to  every  operation  in  dentistry,  and  the  dentist  will  be 
a  much  better  master  of  it  after  one  or  two  attempts. 

When  the  records  of  the  lateral  paths  of  the  condyles  are  sufficiently 
clear,  the  Lateral  Path  Register  is  laid  aside,  and  the  points  of  the  hori- 
zontal pencils  are  placed  opposite  the  heads  of  the  condyles  as  in  Figure 
ISTo.  121.  They  should  be  firmly  locked  in  this  position  since  they  are  to 
serve  as-  guides  for  mounting  the  models  in  correct  positions  on  the 
articulator. 

When  the  pencils  are  in  proper  positions,  a  visiting  card  is  placed 
between  one  pencil  and  the  side  of  the  face  so  that  its  lower  edge  is 
parallel  with  the  broad  plate  supporting  the  pencil  holder.  This  makes 
the  lower  edge  of  the  card  parallel  with  the  occlusal  plane  of  the  trial 
plates.  With  the  card  in  this  position,  the  thumb  screw  controlling  the 
horizontal  position  of  the  broad  plate  is  turned  until  the  spring  behind 
the  pencil  is  about  half  compressed  by  pressure  of  the  pencil  against  the 
card.  The  patient  is  then  asked  to  make  lateral  movements  of  the  man- 
dible with  the  jaws  in  contact,  or  if  this  is  not  possible  to  make  vertical 
opening  and  closing  movements.  The  card  is  held  steady  until  three  or 
four  movements  have  been  made.  Some  patients  record  very  uncertainly 
at  first,  but  after  a  few  moments,  settle  into  the  record  of  a  definite  path. 
In  a  few  cases,  the  records  are  so  indefinite  as  to  have  no  value.  In  such 
cases  it  is  necessary  to  employ  average  adjustments.     See  Fig.  No.  122. 

(Continued  on  Page  1Y8.) 
170 


FlK.   118. 
'I'lic    liKlsor   I'iith    Ucfjistcr  niiil    Horscslioo   I'liitc   in    I'ositiim. 


171 


Fig.  119. 


Vertical   pencils   adjusted    in    position. 
One  method  of  holding  steady. 


Lateral    Path    Register   approaching   oosition. 


172 


Fig.  120. 
LiittTMl   I'ath   i:«-KistrT  ill  coiitnit  wltli  i»encils.     .Aiiotlicr  position  for  boldinir  register 


steady. 


173 


Fig.  121. 
Horizontal    pencils   in   position   and   firmly    locked. 


174 


Fig.    122. 

Ue<oi(liii«    ttie    Forward    Tilth    •>(    tlii'    ( •.iiidylc.*' 


175 


Fig.  123. 
Incisor  Path  Register  recording  horizontal  path  of  incisor  point.     When  the  operator 
is  sufficiently  skillful,  this  path  may  be  recorded  at  the  same  time  as  the  lateral  path. 

176 


FlK.  124. 
An    Incisor    path    Idealized    for    purijoses    of    illustration. 


177 


MEASUEII^G  THE  PATIENT'S  MAi^DIBULAR  MOYE^rEXTS 

(Contimied  from  Page  170.) 

Wlieu  the  record  of  one  condyle  patli  has  been  obtained  in  this  man- 
ner, the  other  end  of  the  card  is  employed  to  register  the  other  condyle 
path  in  like  manner.  The  card  is  laid  aside  with  the  Lateral  Path  Regis- 
ter, for  fntnre  nse.  It  is  important  to  mark  the  paths  "right"  and  "left" 
to  avoid  confusion  later. 

The  Condyle  Path  Register  is  now  removed  from  the  Horseshoe 
Plate  and  the  pin  of  the  Incisor  Path  Register  is  released  so  that  it  can 
record  upon  the  blackened  area  of  the  Horseshoe  Plate.  The  patient  is 
caused  to  make  lateral  movements  of  the  mandible,  with  the  trial  plates 
in  contact,  and  the  pin  will  trace  a  record  in  the  black  wax.  Sometimes 
this  record  will  be  very  indefinite ;  at  others  its  margins  will  be  sharply 
defined.     Only  a  few  intelligent  movements  are  necessary. 

If  the  Incisor  Path  Register  was  mounted  high  enough  above  the 
Horseshoe  Plate  so  that  the  pattern  traced  hj  the  pin  can  be  watched,  the 
dentist  may  gain  useful  information.  In  ninety-nine  cases  out  of  a 
hundred  the  pattern  traced  in  the  wax  will  have  a  round  point  as  long  as 
the  lower  jaw  is  projected  forward  from  its  natural  position  of  rest,  and 
a  sharp  point  when  the  jaw  is  in  a  position  of  rest.  This  is  very  impor- 
tant. 

AYhen  the  pattern  is  satisfactory,  or  is  as  good  as  can  be  gotten, 
the  patient  is  allowed  to  rest  a  moment  so  that  the  point  of  the  pin  is 
ih  the  point  of  the  pattern  it  has  traced.  Marks  are  made  vertically 
across  both  trial  plates  indicating  their  relative  positions,  or  better 
still,  staples  are  inserted  into  the  buccal  surfaces  of  both  plates  fasten- 
ing them  in  correct  positions. 

The  trial  plates,  with  the  Horseshoe  Plate  and  Incisor  Path  Regis- 
ter in  place  are  then  removed  from  the  mouth. 


178 


Fig.  1-25. 

On  the  left,  the  lower  trial  plate  with  the  Horseshoe  Plate  properly  inouuted. 
Ou  the  right,  the  upper  trial  plate  which  has  been  pressed  dowu  upon  the  Horseshoe 
Plate  aud  built  up  in  places  and  pressed  down  agaiu  until  the  pressure  is  even  all  around. 
It  is  important  to  have  this  pressure  even.  Before  recording  the  condyle  paths  tlie  festoons 
made  by  the  Horseshoe  Plate  must  be  trimmed  away,  leaving  a  plane  surface.  A  little 
vaseline  is  applied  over  the  surface  of  the  Horseshoe  Plate. 


Fig.  12(i. 
Upper    and     lower     trial     plates     jxisitioned     by     Incisor    Cuidc     I'in     in     ii.ittcrii     on 
Horseshoe    Plate    and    marks   on    buccal    surfaces.      Correct    vertical    marks    and    incorrect 
sloping   niarlis   shown. 


179 


DETEPailKIlS^G   THE   IXCLIXATIOXS   OF   THE   LATERAL 
PATH  OF  THE  COXDYLE. 

Figs.  Xos.  127-128. 

If  the  lateral  paths  of  the  condyles  were  properly  recorded,  there 
may  be  visible  a  spot,  near  the  beginning  of  each  path,  where  the  line 
seems  to  have  started  and  from  which  it  has  gone  a  little  backward  and 
then  a  much  longer  distance  forward.  This  spot  is  visible  only  when 
the  rotation  centers  of  the  human  jaw  are  "inside  the  condyles,"  a  fact 
which  cannot  be  determined  at  this  time. 

If  such  a  point  is  present  on  each  lateral  path,  a  straight  line  is 
drawn  from  the  point  in  one  path  to  the  similar  point  in  the  other  path, 
by  aid  of  a  ruler.  This  line  serves  as  a  base  line  for  the  calculations 
that  are  to  be  made. 

If  no  such  point  is  present  in  either  path,  a  ruler  is  laid  touching 
the  beginnings  of  both  lines,  and  a  line  drawn  across  each  path  like 
the  line  A-B  in  Fig.  Xo.  127.     This  is  the  base  line. 

The  fact  that  the  base  line  is  drawn  in  this  manner  from  the  begin- 
ning of  one  j)ath  to  the  beginning  of  the  other,  makes  it  unnecessary  to 
hold  the  Lateral  Path  Register  in  any  particular  front  and  back  line 
about  the  head  when  recording  these  paths. 

By  means  of  any  object  presenting  a  right  angle,  such  as  a  visiting 
card,  a  perpendicular  line  is  erected  on  the  base  line  at  the  point  where 
it  crosses  each  lateral  path.  The  tracing  of  the  lateral  path  is  now  pro- 
longed hy  laying  a  ruler  along  its  central  part  and  carrying  the  line 
out  to  the  end  of  the  tab.  The  Degree  Plate  which  accompanies  the 
Gysi  Adaptable  Articulator,  is  now  laid  with  its  0  degree  side  along  the 
perpendicular  erected  on  the  base  line,  and  the  line  of  the  lateral  path  is 
prolonged  with  any  convenient  object  until  it  crosses  the  edge  of  the 
Degree  Plate.  The  inclination  of  the  lateral  path  in  degrees  may  then 
be  read  off  and  recorded  for  future  use.  Such  records  should  be  made 
in  a  permanent  form  as  they  are  often  found  useful  at  future  dates. 

The  inward  inclination  of  the  advancing  condyle  path  may  vary 
from  2  degrees  or  3  degrees  in  a  few  cases,  to  30  degrees  or  more  in  a 
few  cases  at  the  other  extreme.  The  average  inclination  of  a  large 
number  of  records  is  16  degrees. 

The  stationary  condyle  often  records  a  short  but  well  defined  path 
which  generally  leads  outward  from  the  median  line,  and  may  be  in- 
clined either  forward  or  backward.  This  path  is  of  no  known  signifi- 
cance except  as  a  testimony  that  the  centers  of  movement  of  the  human 
mandible  are  not  in  the  condyles,  but  that  lateral  movements  of  the  chin 
are  often  or  always  accompanied  by  a  shifting  of  both  condyles,  the 
chin  and  all  intervening  points,  to  the  same  side  as  the  chin.  It  is  an 
evidence  of  Prof.  Gysi's  wonderful  power  of  analysis  that  in  both  the 
Adaptable  and  Simplex  Articulators,  the  artificial  mandible  can  make 
this  form  of  lateral  motion. 

180 


Fig.  127. 

Lateral  condyle  paths  recorded  and  strengthened.  A-B  line  drawn  from  "i-esting 
point"  in  one  path  to  "resting  point"  in  the  other,  and  perpendiculars  erected  at 
these  points.  Angles  may  be  measured  with  the  Degree  Plate  used  for  measuring 
forward   paths. 


L  17' 


16' K 


13° 

10° 

33" 

IS" 

]no 

1^ 

lis" 

w 

is-^ 

n<' 

Zo^ 

ZO' 

3° 

10° 

10° 

11° 

16" 

i^" 

iZ" 

r 

Fig.   lliS. 

Six  pairs  of  condyles  have  their  inward  lateral  iiiovt-int-ntK  re<<)r(led  in  tlic  trarings. 
Ten  other  pairs  have  their  degrees  of  inward  lateral  movement  recorded  in  the 
central  columns,  but  the  tracings  are  not  given.  The  average  inward  movement  of  these 
16  pairs  of  condyles  is  17  degrees  for  the  left  condyle  and   l(i  degrees  for  the   right. 


181 


MEASUKDsTG    THE    IjSTCLIXATIOX    OF    THE    DOW]NtWAKD 

CONDYLE  PATHS. 

Figs.  Xos.  129-130-131. 

The  downward  paths  of  both  condyles  are  recorded  on  the  visiting- 
card  and  each  is  marked  with  an  initial  showing  its  proper  side  of  the 
head. 

A  line  is  drawn  along  the  center  of  each  path,  ignoring  both  ends 
if  they  are  mnch  cnrved,  and  prolonged  to  the  base  line  of  the  card. 
The  Degree  Plate  is  laid  with  its  0  degree  side  along  the  base  line  of  the 
card  and  its  sharp  angle  at  the  point  where  the  line  through  the  condyle 
path  joins  the  edge  of  the  card.  The  point  where  the  line  crosses  the 
degree  measurements  on  the  Degree  Plate  will  indicate  the  number  of 
degrees  that  the  path  is  inclined  to  the  occlusal  plane. 

Both  paths  are  measured  in  this  way  and  the  degrees  of  inclination 
are  noted  by  the  initial  indicating  the  side.  As  mentioned  in  Part  1, 
all  these  factors  should  form  part  of  a  permanent  record  of  each  case. 

adjusting  the  articulator  to  the  condyle  path 

incli:ntatio]^s. 

At  the  points  marked  "Lateral  Path  Set  Screws"  in  Fig.  jSTo.  114 
will  1)6  found  set  screws  wdiich  govern  the  lateral  inclination  of  the  arti- 
ficial glenoid  fossse.  If  these  screws  are  loosened,  the  plates  forming 
the  roofs  of  the  foss?e  and  marked  ''Adaptable  Lateral  Path"  may  be 
turned  until  the  inward  wall  of  the  fossa  has  been  inclined  to  the  median 
line  the  number  of  degrees  indicated  in  the  lateral  paths,  by  means  of 
the  figures  on  the  upper  surfaces  of  the  plates.  For  lack  of  space  for 
numbers,  the  Fig.  1  on  this  plate  stands  for  10  degrees.  Fig.  2  for  20 
degrees,  etc.  These  adjustments  should  be  made  for  both  sides  and  the 
screws  tightened.  Care  should  be  taken  not  to  confuse  the  sides,  since  it 
is  very  easy  to  mistake  the  left  for  the  right  unless  the  articulator  is  held 
before  one,  with  the  incisor  point  forward. 

At  the  points  marked  "Forward  Path  Set  Screws,"  in  Fig.  No.  114: 
will  be  found  set  screws  which  control  the  downward  inclination  of  the 
glenoid  fossae.  If  the  little  pin  which  projects  from  the  base  of  the 
Incisor  Guide  Pin  marked  "Removable  Pin  For  All  Set  Screws"  be 
taken  from  its  sheath,  it  will  be  found  to  fit  the  hole  pierced  through 
each  of  these  screws,  and  by  it  the  screws  may  be  loosened.  The  plates 
may  be  turned  downward  until  the  pointer  is  at  the  inclination  indi- 
cated by  the  records  of  the  downward  paths  of  the  condyles  on  the  plate 
marked  "Adaptable  Downward  Path."  Care  must  be  taken  not  to 
confuse  the  sides,  in  cases  where  they  are  different. 

The  record  of  the  horizontal  path  of  the  Incisor  Point  cannot  be 
used  until  the  models  are  mounted  on  the  articulator.  It  will  then  be 
used  to  determine  the  horizontal  positions  of  the  Rotation  Points. 

182 


Fig.  iL'll. 
(From  The  Dental  Cosmos,  i 
Analysis  of  right  aud  left  condyle  paths  as  secured  by  the  method  shown  in  Fig.  122, 
C,  Condyle  path.  L.  Left.  K,  Right.  Oc,  Plane  of  occlusion.  35°,  Angle  of  middle  part 
of  path  "to  plane  of  occlusion,  r,  Resting  position  of  condyle.  R^.  Path  of  condyle  in  a 
right  lateral  movement.  L^.  The  same  in  a  left  lateral  movement,  u.  Forward  bite  or 
wide  opening  and  closing  movement. 


Fig.  l^!0. 
Lines  drawn   through  the  central  portions  of  forward   paths  of  condyles. 


Fig.  i:;i. 
.\|.-a>uriiig   two   patlis  similar  to   those  shown   in    Figure   No.   loO. 

183 


■■'it: 


ttC: 


25-: 


kr 


-•'31- 


.37"- 


>^ 


2fi 


■^ 


ii'' 


m'\ 


■w 


\ 


'3d': 


■''2i'. 


m 


z-^ 


33' 


/33"-- 


/-         ^-^ 


J?9» 


(From   The   Dental   Cosmos.) 
Fig.    Jso.    132.      Typical    Forward    Condyle    Paths. 

The  paths  "a"  to  "i"'  inclusive  show   differences  in  form  and  slant  of  the  right  and 
Ifft  paths  in  the  same  patient. 

The  paths  "m"  to  "q"  show  that  other  differences  in  form  or  slant  may  occur  between 
the  path  of  the  opening  movement  and  the  path  of  the  lateral  movement  of  the  mandible. 

The  path  of  the  lateral  movement  alone  has  value  in  the  articulation  of  artificial  teeth. 


184 


POURING  THE  .MODELS. 

The  material  of  which  the  models  are  made  and  the  manner  of 
pouring  may  have  a  great  deal  to  do  with  the  lit  of  the  dentures. 

It  is  my  custom  to  cause  the  rugae  on  the  palatal  surface  of  the 
impression  to  be  deepened  by  carving  and  to  have  the  models  poured 
with  Spence's  plaster.  I  am  indebted  to  Dr.  Tench  for  the  following 
technic  which  we  regularly  employ  and  which  yields  as  tine  models  as  I 
have  ever  seen. 

The  compound  impression  is  given  a  thin  coat  of  either  sandarach 
or  shellac  varnish.  This  is  allowed  to  dry  and  is  followed  by  a  coating 
of  a  water  solution  of  silex  (water  glass).     This  also  is  allowed  to  dry. 

Put  from  one  to  one  and  one-half  ounces  of  water  into  a  clean 
plaster  bowl  and  slowly  add  the  plaster  by  sifting  it  from  the  blade 
of  a  spatula,  at  the  same  time  lightly  jarring  the  bowl  on  the  bench 
to  hasten  saturation.  Continue  adding  plaster  until  no  free  water 
can  be  seen.  Then  spatulate  the  mass  against  the  side  of  the  bowl, 
occasionally  adding  dry  plaster  till  the  mass  becomes  too  stiff  to  work 
easily.     As  it  sets  very  slowly,  no  special  haste  is  necessary. 

Turn  the  contents  of  the  plaster  l)Owl  out  on  a  glass  slab  and  spread 
it  into  the  form  of  a  layer  about  8-10  inches  thick,  by  a  quick  tapping 
motion  of  the  spatula.  This  helps  to  eliminate  air  bubbles  and  im- 
proves the  mix. 

Test  the  consistency  of  the  mix  by  shaping  some  of  it  into  a  cone 
and  standing  it  on  the  slab.  If  it  is  as  resistant  as  fairly  thick  putty 
and  retains  its  shape,  it  is  ready  for  use.  If  it  is  too  thin  to  retain  its 
form,  sprinkle  dry  plaster  over  the  mass  and  incorporate  it  by  the  same 
tapping  motion  used  for  forming  it  into  a  slal». 

If  a  smooth  model  is  desired,  this  plaster  should  never  be  mixed 
80  dry  that  the  surface  will  not  glaze  when  it  is  spread  out  and  patted  as 
described. 

Carry  a  strip  of  the  material  about  Vi  inch  wide  to  the  depression 
formed  by  the  alveolar  ridge,  and  pack  it,  glazed  side  down,  by  a  quick 
tapping  motion  with  the  ball  of  the  index  finger,  working  from  the 
center  of  the  strip  toward  the  heel  of  the  impression.  When  the  material 
is  in  place,  jar  the  impression  on  the  bench  until  the  surface  of  the 
I'laster  glazes.  Add  another  portion  of  plaster  to  that  already  in  position 
tj  building  it  on,  and  patting  and  tapping  in  the  same  way.  In  this 
way  the  palatine  surface  of  the  impression  may  be  covered,  working 
from  ridge  to  center. 

The  model  should  be  l)uilt  u})  until  it  is  about  14  of  an  inch  thick 
at  its  thinnest  place.  The  nuirgins  of  the  model  should  be  shaped  to  be 
vertical  while  the  material  is  soft,  since  it  can  be  trinnned  only  with 
difficulty  after  it  has  set.  These  margins  should  be  flush  with  the 
labial  and  buccal  surfaces  of  the  impression. 

The  ]ow(;r  model  is  packed  in  the  same  manner  except  that  a 
bridrre  of  base  plate  wax  is  form(!d  to  cover  the  opening  in  the  center 
of  tlie  mouth  occupied  by  the  tongue.  Plaster  is  built  over  this,  in  the 
same  manner  as  in  the  upper  impression.  The  resulting  model  is 
mucli  stronger  than  it  would  be  if  the  center  were  left  open. 

185 


THE    RELATIOXS    OF    THE    IXCISOR    POIXT     TO    THE 

COI^DYLES. 

I  believe  it  to  be  important  to  mount  the  trial  plates  so  that  the 
incisor  point  is  at  the  same  distance  from  the  artificial  condyles  that  it  is 
from  the  natural  condyles  in  the  patient  for  whom  the  dentures  are  in- 
tended. I  believe  it  to  be  well  also  that  the  occlusal  plane  shall  be  at  the 
same  distance  below  the  level  of  the  condyles  as  in  that  particular 
patient.    Both  of  these  ends  may  be  easily  achieved. 

It  was  shown  on  page  153  that  the  horizontal  distance  between  the 
condyles  had  little  effect  on  the  forms  of  the  teeth  or  the  depth  of  the 
bite.  It  has  less  influence  on  the  movements  of  the  teeth,  because  the 
condyles  are  not  the  centers  of  movement.  But  if  the  trial  plates  are 
mounted  at  the  right  distance  from  the  condyles,  they  must  be  at  right 
distances  forward  from  the  rotation  points  also.  And  that  comes  much 
nearer  the  re-establishment  of  the  mandibular  triangle  for  that  patient, 
than  the  mounting  of  the  trial  j)lates  by  chance.  The  more  nearly  the 
mandibular  triangle  is  reproduced,  the  more  nearly  correct  will  be  the 
incisor  movements  of  the  trial  plates,  and  the  more  comfortable  and 
efficient  the  dentures  will  be.  The  movements  of  the  incisor  points  are, 
as  has  l:)een  explained,  the  most  important  of  the  denture  movements, 
because  if  they  are  correct,  the  movements  of  the  other  parts  are  nearly 
sure  to  be  right. 

There  is  another  important  reason  why  the  trial  plates  should  be 
mounted  on  the  articulator  in  right  relations  to  the  condyles.  It  is  that 
the  triangle  formed  by  the  two  condyles  and  the  incisor  point,  commonly 
referred  to  as  "Bonwiirs  triangle,"  is  rarely  symmetrical;  that  is,  it 
is  rarely  four  inches  on  a  side.  The  incisor  point  is  often  so  far  to  one 
side  of  where  Bonwill's  measurements  would  bring  it,  that  it  may  make 
considerable  difference  as  to  whether  or  not  it  is  correctly  located. 

The  illustrations  on  the  opposite  page,  from  Dr.  Frahm's  article 
in  The  Dental  Cosmos  of  May  1914,  illustrate  not  only  the  difference 
in  size  of  different  human  mandibles,  but  the  fact  that  the  triangles 
erected  on  the  bases  of  different  human  skulls  are  often  not  equilateral, 
as  Bonwill  thought,  and  that  the  incisor  point  is  often  considerably  at 
one  side  of  the  point  where  Bonwill  located  it. 

The  trial  plates  may  be  mounted  on  the  articulator  so  that  the 
incisor  point  is  at  the  right  distance  forward  of  the  condyles  and  the 
occlusal  plane  is  at  the  right  distance  below  the  condyles,  and  the  in- 
cisor point  is  in  the  horizontal  position  peculiar  to  that  patient,  by  the 
use  of  the  Condyle  Path  Register  accompanying  the  G-ysi  Adaptable 
Articulator,  or  the  Snow  Face  Bow  which  may  be  used  with  the  Gysi 
Simplex  Articulator. 


186 


Fig.   A. 
Theoretical    equilateral    triangle. 


-f-3  m.i 


Fig.   B. 

Not    four    inches    on    a    side    and    not 

equilateral. 


/<7/mn,- 


Fig.   C.  Fig.  D. 

Incisor   point   at   right   of   middle   of   base.        Incisor    point    at    left    of    middle    of    base. 


Fig.   K. 
lucisor    iioint    at    left    of    mi 


111-    of    base. 


Fig.    F. 
Far    from    ocjuilateral. 


Fig.  i:j:!. 

I)r.  I'rahm's  drawings  showing  that  the  mandibular  triangle  is  not  equal  sided  and 
that  the  incisr»r  iioliit  Is  often  not  in  tlie  median  line  of  the  base.  (From  the  Dental 
('osinos.^ 


187 


MOUNTIA^G  THE  MODELS  ON  THE  ADAPTABLE  ARTICU- 
LATOR. 

Fig.  No.  134. 

When  the  models  are  ready  for  mounting,  the  Condyle  Path  Pegis- 
ter  is  mounted  on  the  Gooseneck  and  its  holder,  see  Figs.  Nos.  115  and 
134,  by  fitting  the  hole  in  the  front  of  the  block  on  the  Register  over  the 
end  of  the  Gooseneck. 

The  models  are  put  into  the  trial  plates  and  preferably  fastened 
there  by  the  application  of  wax  along  the  margins  of  the  trial  plates. 
The  tops  of  the  models  are  soaked  in  water  to  facilitate  attachment  to 
the  model  bows.  If  the  trial  plates  were  not  fastened  together  in  correct 
relations,  as  described  on  page  178,  they  are  now  placed  in  right  rela- 
tions by  locating  the  pin  of  the  Incisor  Path  Register  in  the  apex  of 
the  pattern  traced  on  the  Horseshoe  Plate,  and  bringing  the  marks 
across  the  buccal  surfaces  of  both  trial  plates  into  right  relations.  These 
relations  will  be  much  more  easily  established  if  the  marks  have  been 
made  vertically  after  the  manner  marked  "good"  in  Fig.  No.  12G.  When 
the  trial  plates  are  in  right  relations,  they  are  fastened  so  by  w^arming 
the  wax  at  their  occlusal  edges,  or  by  putting  staples  into  the  buccal 
surfaces  or  by  passing  a  cord  around  both. 

The  Horseshoe  Plate,  with  the  trial  plates  and  models  attached,  is 
now  mounted  on  the  inside  of  the  Condyle  Path  Register,  by  thrusting 
the  two  projecting  arms  of  the  plate  into  the  two  holes  in  the  block  of 
the  Register. 

The  curved  Incisor  Guide  Pin,  (part  3,  Fig.  115)  is  now  placed  in 
the  opening  in  the  upper  model  bow,  with  the  top  of  the  pin  flush  with 
the  top  of  the  opening.  The  Gooseneck,  with  its  attachments  is  moved 
until  the  ends  of  the  horizontal  pencils  are  opposite  and  equally  distant 
from  the  ends  of  the  condyles.  These  vertical  relations  can  be  attained 
by  raising  or  depressing  the  Gooseneck  in  its  holder.  The  plates  sup- 
porting the  pencil  holders  must  not  be  moved. 

Plaster  may  be  poured  onto  the  upper  model  attaching  it  to  the 
upper  bow  in  these  relations,  or  the  Gooseneck  and  attachments  may  be 
moved  away  and  plaster  poured  over  the  lower  model  bow  and  the  Goose- 
neck replaced  so  that  the  pencils  are  in  right  relations.  If  the 
plaster  is  poured  over  the  upper  model  first,  it  will  be  necessary  to 
invert  the  articulator  and  models  w^hen  the  plaster  is  hard  and  attach 
the  lower  model  to  its  bow.  If  the  lower  model  is  moved  into  the 
plaster  on  the  lower  bow,  it  is  necessary  only  to  pour  plaster  on  the  upper 
model  and  let  all  harden. 

DETERMINING  THE  HORIZONTAL  LOCATIONS  OF  THE 

ROTATION  POINTS. 

Fig.  No.  135. 

When  the  models  are  firmly  attached  to  the  model  bows,  remove  the 

Gooseneck  and  Condyle  Path  Register.     Loosen  the  trial  plates  so  that 

(Continued  on  Page  190.) 
188 


Fig.  VM. 
Mountiuj:   the  trial   plates  an.l   nuMlels   by   means  uf   The   ('..iHlyle   I'ath    Register,   and 
the  bent   Ineisor  (iuide  I'in. 


Fig.  i:'.5. 
Locating    the    Horizontal    Position    of    the    Rotation    I'oints 

189 


(Continued  from  Page  188.) 

one  can  move  on  the  other.  Lift  the  Incisor  Path  Eegister  Pin  from  the 
Horseshoe  Plate.  Push  both  Rotation  Points  as  near  the  median  line 
as  j)ossible.  Move  the  upper  model  laterally  and  see  if  the  center  of 
the  Incisor  Path  Register  follows  the  outline  of  the  pattern  on  the 
Horseshoe  Plate.  Move  the  Rotation  Point  in  action  for  that  movement 
outward  until  it  does  follow,  and  lock  it  in  that  position.  Adjust  the 
other  Rotation  Point  so  that  the  Incisor  Path  Register  follows  the 
other  side  of  the  pattern  on  the  Horseshoe  Plate.  Then  lower  the  pin 
of  the  Incisor  Path  Register  and  make  sure  that  it  follows  the  margins 
of  the  pattern  as  closely  as  possible  in  both  lateral  movements. 

If  the  pattern  on  the  Horseshoe  Plate  was  unlike  on  the  two  sides 
of  the  median  line,  the  Rotation  Points  will  be  unequally  distant  from 
the  median  line. 

The  articulator  and  trial  plates  are  now  ready  for  the  teeth. 

ATTACHIXG  THE  MODELS  TO  THE  GYSI  SIMPLEX  ARTIC- 
ULATOR. 
Pigs.  Xos.  136,  137,  138,  139. 

The  models  may  be  attached  to  this  articulator  by  the  use  of  the 
Snow  Face  Bow  or  by  establishing  on  the  articulator  the  equilateral 
triangle  commonly  referred  to  as  "Bonwill's  triangle." 

If  the  Snow  Face  Bow  is  to  be  used,  the  semicircular  end  of  the 
Mouth  Piece  accompanying  the  Bow  must  be  warmed  and  thrust  into 
the  labial  surface  of  a  trial  plate,  preferably  the  upper,  a  short  distance 
above  the  occlusal  plane,  and  as  nearly  parallel  with  the  occlusal  plane 
as  is  convenient,  and  with  the  stem  of  the  Mouth  Piece  projecting 
forward  in  the  median  line  of  the  plate.     It  must  be  iirmly  seated. 

The  location  of  the  head  of  each  condyle  is  marked  on  the  face. 
The  trial  plates,  fastened  together  in  proper  biting  relations,  and  with 
the  mouth  piece  attached  as  described,  are  placed  in  the  mouth  and  the 
patient  is  asked  to  close  the  jaws  into  them. 

When  the  trial  plates  and  mouth  piece  are  in  position,  the  Face 
Bow  is  passed  about  the  face,  the  stem  of  the  Mouth  Piece  goes  through 
the  swivel  nut,  and  the  ends  of  the  pointers  are  placed  over  the  marks 
locating  the  heads  of  the  condyles.  The  swivel  pointers  are  pressed  iirmly 
in  against  the  face,  and  the  bow  is  moved  from  side  to  side  until  an  equal 
number  of  marks  on  each  pointer  is  between  the  lock  nut  and  the  face. 
The  lock  nuts   about  the  swivel  pointers   are  then  tightened. 

The  lock  nut  of  the  swivel  block  is  then  tightened  very  firmly.  This 
locks  the  mouth  piece  in  proper  relations  to  the  arch  of  the  Face  Bow. 
It  establishes  the  distance  of  the  incisor  point  from  the  condyles  as  it 
is  in  that  patient,  and  the  correct  relation  of  the  incisor  point  to  the 
median  line. 

The  lock  nuts  about  the  pointers  are  now  loosened,  the  pointers 
moved  outward,  the  patient  is  asked  to  open  the  mouth,  and  the  arch, 
mouth  piece  and  trial  plates  are  removed  as  one  piece.     The  models  may 

190 


ATTAC'lIlXCi  THEMODELS  TO  THE  GVSl  SIMl'LKX  AimC- 
ULAT(  )K,   (  ( 'ontiuucd  ). 

now  be  poured  into  the  trial  plates  and  Iriniiiied  for  mount ini^-  on  the 
articulator. 

On  the  condyles  of  the  Gysi  Simplex  Articidator,  will  he  found 
two  Face  Bow  Adapters  for  receiving  the  depressions  in  the  inner  ends 
of  the  sliding  pointers  of  the  Face  I>ow  of  the  articulator.  Tush  the 
sliding  pointers  as  far  in  as  they  will  go  and  lock  them  there.  Lift 
the  upper  model  bow.  Spring  the  ends  of  the  sliding  pointers  over  the 
knol)s  on  the  Face  Bow  Adapters. 

Wet  the  models.  Pour  plaster  over  the  lower  model  how  and  move 
the  models  down  into  it  until  the  occlusal  plane  of  the  trial  plates  is  level 
with  the  tahle  on  which  the  articulator  sits.  When  the  attachment^  to 
the  lower  how  is  hard,  remove  the  face  bow  and  mouth  piece  by  heating 
the  stem,  wet  the  upper  model  and  pour  plaster  on  it,  and  bring  the 
upper  model  bow  down  until  the  pin  is  touching  the  Incisor  Guide 
Incline.  The  top  of  the  pin  shoidd  be  level  with  the  top  of  the  opening 
which  holds  it. 

If  it  is  not  desired  to  attach  the  models  to  the  articulator  by  means 
of  the  Face  Bow,  they  may  easily  be  attached  so  that  distance  from  the 
condyles  to  the  incisor  point  shall  be  etjual  to  the  distance  between  the 
condyles.     This  forms  BonwilTs  Triangle. 

On  the  Incisor  Guide  Pin  will  be  found  a  pointed  metal  block  called 
The  Incisor  Guide,  because  it  locates  the  incisor  point  in  this  method 
of  mounting.  Plaster  should  be  poured  over  the  lower  model  bow  and 
the  upper  model  bow  closed  so  that  the  Incisor  Guide  Pin  rests  on  the 
Incisor  Guide  Incline,  the  top  of  the  pin  being  flush  with  the  top  of  the 
opening  in  which  it  is  held.  The  models  having  been  previously  wet,  the 
models  and  trial  plates  are  passed  between  the  model  bows  and  so  located 
that  the  incisor  point  of  the  trial  plates  touches  the  Incisor  Guide,  while 
the  occlusal  ])lane  is  on  the  l(!vel  from  the  Incisor  Guid(!  to  the  projec- 
tions on  the  inner  sides  of  the  upright  part  of  the  articulator  frame. 
Care  should  be  taken  that  the  models  are  located  evenly  on  both  sides 
of  the  upper  model  bow.  l^laster  nuiy  now  be  poured  on  the  upper  model 
and  model  bow. 

When  the  plaster  has  hardened,  the  attachmciit  of  the  models  to 
the  articulator  is  complete. 

This  method  is  open  to  the  ol)j(!Ction  that  it  is  ])urely  arbitrary  and 
is  not  suited  to  the  recpiirements  of  tlie  individual  patient.  It  is,  how- 
ever, more  satisfactory  in  this  articulator  than  in  other  simple  articula- 
tors because  the  Kotation  Points  are  here  in  the  proper  vertical  position, 
and,  as  explained  in  connection  with  Figs.  Xos.  !>4  and  05,  this  tact 
has  trreat  influence  on  tlie  ai't  icnial  ion  of  the  dciihires. 


191 


Fig.  136. 
Patient  with  Snow  Face  Bow  in  position. 


Fig.  137. 
Trial  plates  mounted  on  Simplex  articulator  with  Face  Bow. 


192 


Fifi.  l:!S. 

If  the  models  be  so  mounted  that  the  distance  t<p  the  median  line  of  the  trial  plates, 
at  the  occlusal  plane,  equals  the  distance  between  the  depressions  on  the  horizontal  plates 
over  the  fossae,  they  will  conform  to  Dr.  Bonwill's  measurements.  The  line  O-O  from  the 
center  of  the  depression  in  The  Incisor  Guide  Pin  to  the  projection  X'  im  the  inner  side 
of  the  frame  represents  the  proper  level  of  the  occlusal  plane. 


Models   iiioiinti-d   by  nie.-iMs   <,f  t  hr'    Iijiisur  (liiick 


193 


PART   VII. 


Articulating  The  Teeth 


MAKIXG  WAX  TEIAL  PLATES. 
Fig.  l\o.  140. 

If  the  impression  taking  and  trial  plate  making  methods  outlined  in 
Part  I  have  been  followed,  the  trial  plates  now  on  the  models  are  made 
of  modelling  compound  and  are  not  suitable  for  the  arrangement  of 
the  teeth.     These  trial  plates  must  be  replaced  with  others. 

Before  removing  either  of  the  trial  plates,  continue  the  median 
line  marked  on  the  plates  across  both  plaster  models.  Mark  on  the  upper 
plaster  model  a  line  parallel  to  the  occlusal  plane,  as  in  Fi^'.  No.  140, 
line  A-A.  Mark  olf  on  this  line  a  distance  from  the  median  line  equal 
to  the  distance  from  the  line  A-A  to  the  high  lip  line  and  a  distance  equal 
to  the  distance  from  this  line  to  the  occlusal  plane,  so  that  if  bj  any  acci- 
dent the  height  of  the  bite  is  lost,  it  may  be  re-established.  It  is  well 
also  to  make  a  similar  horizontal  line  on  the  lower  trial  plate  and  mark 
the  distance  from  the  low  lip  line,  and  the  occlusal  plane. 

Take  the  upper  trial  plate  from  the  model,  marring  it  as  little  as 
may  be.  It  may  usually  be  removed  by  warming  or  carving  the  edges 
of  the  impression  part.  Shape  over  the  upper  model  a  base  and  adapt 
it  carefully,  especially  between  the  rugae  which  have  been  made  a  little 
higher  than  normal  by  carving  the  impression.  Such  adaptation  may 
prevent  the  trial  plate  taking  a  false  position  when  tried  into  the  mouth. 

For  such  bases  I  prefer  Dentsply  Baseplate  Composition  because 
it  is  stiffer  than  wax,  does  not  need  to  be  wired  to  prevent  warping,  as 
wax  does,  and  because  in  especial  cases  it  may  be  strengthened  by  build- 
ing additional  composition  about  the  rim  in  the  same  way  that  the  mar- 
gins of  the  impression  were  built  up.  It  should  be  warmed  over  a  small 
flame,  roughly  adapted  and  trimmed  and  then  further  adapted  until  it 
is  of  the  form  of  the  finished  denture. 

The  ridge  of  the  trial  plate  is  to  be  made  of  baseplate  wax,  and 
should  be  shaped  like  the  ridge  of  the  upper  trial  plate  which  has  been 
removed.  This  can  usually  be  well  done  by  building  it  out  to  the 
margin  of  the  lower  trial  plate,  and  then  building  the  labial  fullness  up 
as  desired. 

The  kind  of  wax  used  for  these  ridges  makes  a  good  deal  of  dif- 
ference in  the  future  work*  Some  baseplate  waxes  hold  the  teeth  well 
in  position,  while  others  make  it  impossible  to  keep  the  teeth  in  position. 
I  believe  the  final  work  is  often  unsatisfactory  because  a  wax  was  used 
which  allowed  the  teeth  to  easily  change  position  during  the  final  steps 
of  articulation. 

In  order  that  Prof.  Gysi's  method  of  automatic  articulation  may 
be  put  into  operation,  the  wax  must  hold  the  teeth  well  in  position.  I 
prefer  Dentsply  Baseplate  Wax  for  this  purpose. 

The  lower  trial  plate  of  modelling  compound  is  now  removed  from 
the  model,  a  base  of  baseplate  composition  is  carefully  adapted  to  the 
ridge,  and  a  wax  ridge  is  built  upon  it  after  the  manner  employed  in 
making  the  upper  trial  plate.  This  plate  should  be  given  any  peculiari- 
ties of  form  which  suit  it  to  the  case  in  hand. 

196 


Fig.  140. 
norizont.1   lines   on   upper   and   lower   models,   with    distances  to   hi.M,   and   low   lines 
and  occlusal  planes  marked   on  them. 


iltff^SKTfS^V?^ ' 


Fig.  141. 
Setting    upper    anteriors,    beginning    at    median    line. 


1 


Fig.   14: 


Setting  lower  .-us s  In   right    relations  to  u| r  .uspi.ls  and   laterals. 

]!)7 


SETTIIs^G  THE  A^'TERIOR  TEETH. 
Figs.    ^^os.    141,    142,    143,    144,    145,    146. 

Recesses  may  now  be  cut  in  the  wax  of  the  upper  trial  plate  on  one 
side  of  the  median  line,  and  the  upper  central,  lateral  and  cuspid  for 
that  side  put  in  position,  making  sure  that  their  labial  surfaces  restore 
the  contour  of  the  wax. 

Set  the  upper  central  lateral  and  cuspid  of  the  other  side  in  like 
manner. 

The  position  given  the  upper  and  lower  cuspids  will  have  a  great 
eifect  on  the  appearance  of  the  denture.  If  the  cuspids  be  rotated  as 
in  Fig.  ISTo.  000,  the  result  will  be  pleasing,  but  if  the  distal  portion 
of  the  labial  surface  of  the  upper  cuspid  be  inclined  too  much  forward, 
the  appearance  will  be  displeasing.  This  position  will  be  governed 
slightly  by  the  width  of  the  arch,  but  an  effort  should  be  made  to  turn 
this  surface  as  shown  in  the  illustration. 

When  the  upper  anteriors  are  set,  recesses  are  cut  in  the  wax  of  the 
lower  trial  plate  and  the  lower  cuspids  are  set.  These  are  the  most  diffi- 
cult teeth  in  both  dentures  to  arrange,  and  a  little  care  spent  at  this 
time  will  be  repaid  in  better  results. 

The  distal  angle  of  each  lower  cuspid  should  come  just  below  the 
tip  of  the  upper  cuspid.  The  distal  facet  on  the  cutting  edge  of  the 
lower  cuspid  should  occlude  with  the  mesial  facet  on  the  upper  cuspid, 
while  the  mesial  facet  on  the  cutting  edge  of  the  lower  cuspid  should 
occlude  with  the  short  facet  on  the  distal  portion  of  the  cutting  edge 
of  the  upper  lateral.  On  all  teeth  except  T  mbyte  teeth,  it  will  be  neces- 
sary to  grind  these  facets  with  care.  When  the  jaw  moves  laterally  these 
teeth  must  articulate  without  leaving  contact.  A  careful  study  of  the 
relations  shown  in  Figures  143  and  144  will  be  helpful  in  learning  to 
establish  these  relations. 

When  both  lower  cuspids  are  in  correct  positions,  the  lower  incisors 
may  be  set  between  them.  Some  little  grinding  may  be  necessary 
on  the  distal  surfaces  of  the  lower  laterals  to  establish  right  relations, 
and  it  may  be  thought  that  this  is  an  evidence  that  the  teeth  have  not 
been  carefully  manufactured.  If  much  grinding  is  necessary,  such  a 
conclusion  is  just,  but  when  only  a  little  grinding  is  required,  the  con- 
clusion is  not  just. 

The  ideal  arrangement  of  the  lower  anteriors  is  for  them  to  under- 
bite  the  upper  anteriors,  just  enough  so  that  the  lower  incisors  are  out  of 
contact  with  the  uppers  when  the  jaw  is  in  central  occlusion,  and  so  that 
the  edges  of  the  uppers  and  lowers  articulate  during  lateral  movements. 
Very  deep  underbites  should  not  be  sought,  since  they  tend  to  dislodge 
the  dentures,  and  since  they  are  hardly  possible  with  correct  relations  of 
the  upper  and  lower  cuspids.  Fig.  145  illustrates  correct  and  incorrect 
incisor  relations. 

198 


Fig.  143. 
Above,  correct  vertical  relations  of  upper 
ind  lower  anteriors.  Below,  correctly 
"ormed  facets  on  lower  cuspid.  Lower 
;uspid  properly  rotated  and  bicuspids 
partl.v   hidden    behind   it. 


Fig.  145. 
The  effect  on  the  stability  of  the  dentures 
and  on  the  expression  of  correct  and  incor- 
rect relations  of  upper  and   lower  incisors. 


CUSPID 
REUATIONS 
IN  CENTRAL 
OCCLUSION 


0. 


CUSPID 

BELATIONS    ON 
THE  WORKING      ,     ,.,^ 
SIDE  IN  lateral/     T^ 
ARTlCULATfON 


Fig.   144. 


Fig.  140. 
A   straight  edge   laid   on   the   mesial   facet 
of    the    upper   cuspid,    as    liere    shown,    will 
touch   tlie  gum  at  the  mesio-lingual  root  of 
tlic   lirst    iiiohir  of   the   (ppposite   side. 


IDD 


SETTING   THE   AXTEKIOR   TEETH— Continued. 

Figs.  Xos.  147  and  l-iS. 

The  beauty  of  the  dentures  will  be  largely  influenced  by  the  posi- 
tions of  the  anterior  teeth. 

The  first  of  these  relations  to  attract  the  dentist's  attention  is  that 
determined  by  the  distal  divergence  of  the  roots.  In  the  typical  case, 
the  roots  of  the  upper  centrals  are  parallel;  the  roots  of  the  upper 
laterals  diverge  distally  from  those  of  the  centrals;  the  roots  of  the 
upper  cuspids  diverge  distally  less  than  do  the  laterals ;  the  roots  of 
the  two  upper  bicuspids  are  parallel  with  those  of  the  upper  centrals, 
and  the  root  axis  of  the  upper  first  molar  actually  slopes  forward 
toward  the  centrals.     These  relations  are  shown  in  Fig.  ]^o.  147. 

The  roots  of  the  four  lower  incisors  do  not  diverge  distally  from 
the  median  line,  but  the  roots  of  the  lower  cuspids  diverge  distally  in 
a  marked  degree.  The  root  positions  of  the  lower  bicuspids  and  molars 
will  be  determined  by  articulation  with  the  upper  teeth. 

The  labial  inclination  of  the  anteriors  is  equally  important,  be- 
cause more  dentures  are  made  to  look  unnatural  from  errors  in  this 
inclination  than  in  any  other.  The  tendency  is  always  to  place  the 
necks  of  the  incisors  too  far  forward  in  relation  to  the  positions  of  the 
cutting  edges.  As  can  be  seen  by  reference  to  Fig.  jSTo.  145,  this  gives 
the  lips  an  unnatural  fullness. 

The  correct  inclination  for  the  upper  centrals  is  shown  in  "c"  of 
Fig.  'No.  148.  This  inclination  brings  the  facets  on  the  cutting  edges 
into  the  most  effective  articulation  with  the  edges  of  the  lower  incisors. 
The  neck  of  each  upper  lateral  is  set  a  little  farther  back  than  the  necks 
of  the  upper  centrals,  as  shown  in  ''1"  of  Fig.  jSTo.  148. 

The  upper  cuspids  stand  more  nearly  upright  than  either  the 
centrals  or  laterals.  This  helps  to  build  up  the  cuspid  eminences  as 
shown  in  "C"  of  Fig.  ISTo.  148.  The  articulating  facets  on  the  cuspids 
are  but  little  inclined  upward  from  horizontal. 

The  labial  positions  of  the  lower  centrals,  laterals  and  cuspids, 
are  shown  in  '^c,"  "V  and  "C"  of  Fig.  :^o.  148.  The  edges  of  the  lower 
centrals  incline  strongly  forward.  Dentures  are  very  common  in  which 
these  teeth  are  either  set  vertically  or  inclined  inward.  The  effect  on 
the  expression  of  the  lip  is  shown  in  Fig.  jSTo.  145. 

The  lower  cuspid  necks  are  prominent  and  help  build  out  the  cus- 
pid eminences.  The  articulating  facets  on  the  lower  cuspids  are  parallel 
to  those  on  the  upper  cuspids. 


200 


Fit;.  l^T. 
Mesio-Distal  iiiclhiiitiou   <>f   the   tectli. 

The  roots  of  the  upper  centrals  are  parallel.  The  roots  of  the  upper  laterals  and 
cuspids  diverge  from  the  median  line,  the  laterals  diverging  slightly  more  than  the 
cuspids.  The  roots  of  the  upper  bicuspids  are  parallel  with  those  of  the  upper  centrals, 
while  the  roots  of  the  first  molars  incline  slightly  toward  the  mesial.  This  position  of 
the  upper  first  artificial  molar  is  probably  a  compromise  betv\een  the  positions  of  the 
first  and   second  natural  molars. 

The  roots  of  the  lower  centrals  and  laterals  are  parallel,  but  those  of  the  lower 
cuspids   diverge   strongly. 


Fig.  148. 
Forward  inclinations  of  the  anterior  teeth. 

The  best  effects  are  obtained  by  inclining  the  upper  centrals  as  shown  at  "c."  This 
not  only  gives  the  most  pleasing  esthetic  effect,  but  brings  the  facets  on  the  cutting 
edges    into    the    inclination    wliich    articulates    most    efliciently    with    the    lower    incisors. 

The  necljs  of  the  ujiper  laterals  should  sit  bacli  more  than  those  of  the  upper  centrals, 
though  the  rutting  edges  are  nearly  as  far  forward.  It  will  be  noted  that  the  articulating 
facet  on  the  cutting  edge  is  less  steeply  inclined  than  that  on  the  central.  This  is  the 
inclination  of  the  mesial  facet  on  the  lateral. 

The  cuspids  stand  more  nearly  vertical  tlian  either  the  centrals  or  laterals,  and  the 
facets  on   the  edges  are  nearly   horizontal. 

The  lower  centrals  slope  strongly  outward  from  neck  to  incisal  edge.  This  pre- 
vents the  over  fullness  of  the  gums  so  common  to  lower  dentures,  and  illustrated  in 
Fig.   No.  14."*. 

The  lower  laterals  slope  outward   very   much   less  th;in    do   the  centrals. 

The  necl{s  of  the  lower  cuspids  an;  very  prominent  while  tlic  cutting  edges  are 
pretty  well  back.  This  causes  the  necks  t<.  be  prominent  iind  lill  (nit  tlie  cuspid  eminence, 
and   causes   the  teeth   to   slope  inward    frnni    the   gum    up. 

201 


RELATIVE  WIDTHS  OF  UPPER  AND  LOWER  AN^TERIOR 

TEETH. 

Fig.   N^o.    149. 

It  is  rare  that  the  upper  and  lower  anterior  teeth  go  exactly  to 
place  without  some  grinding  of  one  set  or  the  other  to  establish  correct 
relative  widths.  The  amount  of  grinding  depends  on  the  care  with 
which  the  manufacturer  has  complied  with  the  requirements  of  articu- 
lation, on  the  particular  arrangement  of  anterior  teeth  favored  by  the 
dentist,  and  on  the  articulating  movements  in  the  case  in  hand.  The 
best  results  will  be  obtained  if  the  dentist  and  manufacturer  both  under- 
stand what  part  of  the  work  each  should  perform. 

It  is  the  manufacturer's  duty  to  supply  upper  and  lower  anteriors 
of  such  relative  widths  that  the  dentist  can  easily  adapt  them  to  the 
requirements  of  any  ordinary  case.  They  should  not  be  much  too  wide 
for  the  dentist  who  wishes  to  set  the  lower  incisors  pretty  well  back  ot 
the  upper  incisors,  or  much  too  narrow  for  the  dentist  who  wishes  to  set 
them  irregularly. 

On  the  other  hand,  the  dentist  must  not  expect  that  the  manu- 
facturer can  supply  upper  and  lower  anteriors  which  are  of  exactly 
the  correct  relative  widths  to  permit  different  forms  of  arrangement. 
This  would  require  hundreds  of  moulds  of  anteriors,  nor  could  the 
dentist  know  which  of  the  hundreds  of  moulds  was  needed  until  he  set 
the  teeth  on  the  case.  He,  the  dentist,  should  recognize  it  as  his  task 
to  adapt  a  correctly  formed  product  to  his  own  special  requirements. 

The  widths  of  the  upper  and  lower  anteriors  are  affected  by  the 
horizontal  location  of  the  rotation  points,  as  is  made  clear  by  a  study 
of  Fig.  ]^o.  149.  The  large  diagram  shows  the  path  of  the  buccal 
cusp  of  the  upper  first  bicuspid  in  three  different  horizontal  locations 
of  the  rotation  points.  When  the  rotation  points  are  in  the  position 
marked  ''R  i,"  the  upper  bicuspids  move  through  the  path  marked  "R  i." 
When  the  rotation  point  is  opposite  the  condyles,  the  upper  bicuspids 
move  through  the  path  marked  ^'R  m."  When  it  is  outside  of  the 
condyles,  the  upper  bicuspids  move  through  the  path  marked  "R  a." 
The  practical  application  of  these  movements  to  the  width  of  the  upper 
and  lower  anteriors  is  seen  in  Figs.  D-E-F. 

In  Fig.  149D  the  relative  widths  of  upper  and  lower  anteriors 
necessary  for  the  path  "R  i"  is  shown.  The  upper  anteriors  are  here 
quite  a  little  wider  than  the  lower  anteriors  so  that  the  tip  of  the 
upper  cuspid  may  pass  through  the  interdental  space  distal  to  the  lower 
cuspid  during  lateral  movements.  In  Fig.  149E  the  tip  of  the  upper 
cuspid  is  just  above  the  distal  angle  of  the  lower  cuspid.  In  Fig.  149F 
the  tip  of  the  upper  cuspid  is  just  anterior  to  the  distal  angle  of  the 
lower  cuspid,  in  order  that  it  may  pass  through  the  interdental  space 
posterior  to  the  lower  cuspid  when  the  rotation  point  is  located  at  "R.a." 

Trubyte  teeth  are  designed  to  produce  the  cuspid  relations  shown 
in  Fig.  149E,  with  a  minimum  of  grinding. 

202 


R.i      D 


R.m   E 


R.a     F 


Fig.  149. 

Diagram  showing  three  paths  of  the  upper  left  first  bituspid  with  three  different 
horizontal  locations  of  the  rotation  points.  "R  i"  indicates  a  location  of  the  rotation 
points  between  the  condyles  and  the  median  line.  "R  m"  indicates  a  location  at  the 
condyles,  and  "R  a"'  a  location  outside  the  condyles. 

The  movements  of  the  upper  first  bicuspid  are  indicated  by  the  paths  numbered 
like  the  rotation  point   fiM.ni   which  each  movement  is  inscribed. 

The  movements  of  the  incisor  point  are  shown  by  three  paths  drawn  from  the  incisor 
point  and  numbered  like  the  centers  from  which  they  are  taken. 

The  figures  "D-E-F"  show  the  relative  wi<lths  of  the  upper  and  lower  anteriors 
ne«essary  to  make  possible  the  correct  movement  of  the  points  of  the  upper  cuspids 
through   these  three  paths. 

It  will  be  noted  that  in  Fig.  1»  the  points  of  the  upper  anteriors  are  quite  a  little 
wider  than  the  lower  anteriors  and  the  points  of  the  upper  cuspids  need  to  come  a  little 
to  the  distal  of  the  distal  angles  of  the  lower  cuspid,  to  make  it  possible  for  the  point 
of  the  upper  cusjjid  to  follow  the  path  "It  i." 

In  Figure  F  the  points  of  tlic  upper  cuspids  need  t.i  come  a  little  anterior  to  the 
distal  angle  of  the  lower  cuspids,  to  inaUc  it  possihh-  to  follow  the  path  "U  a." 

This  diagram  helps  make  it  idiiiii  why  a  given  width  of  upper  and  lower  anteriors 
Is  not  e.xactly  suitable  for  .til  cases. 


2o;j 


GRI1^^DIXG  A^^TERIOR  TEETH  TO  FORM. 
Figs.  Xos.  143,  144-,  146,  148,  149. 

Dentists  who  prefer  not  to  use  Trubyte  teeth  may  grind  an}^  other 
anterior  teeth  to  such  articulating  forms  as  the  teeth  permit  and  their 
own  skill  makes  possible.  A  few  simple  directions  for  such  grinding 
may  be  helpful. 

The  cutting  edges  of  the  upper  incisors  should  present  facets  for 
articulation  with  the  lower  anteriors.  If  the  teeth  are  to  be  set  in  the 
typical  positions  shown  in  Figs.  ISTos.  143  and  144,  the  facets  should 
be  of  the  forms  shown  in  Fig.  ]Sro.  146  and  have  the  inclinations  shown 
in  Figs.  N^os.  144  and  148. 

It  will  be  noted  that  the  cutting  edge  of  each  upper  lateral  pre- 
sents two  facets,  of  which  the  mesial  is  the  longer.  This  mesial  facet 
articulates  with  the  cutting  edge  of  the  lower  lateral,  and  should  have 
the  inclination  of  the  facet  shown  in  the  upper  lateral  in  Fig.  ISTo.  148. 
The  distal  facet  articulates  with  the  mesial  facet  on  the  lower  cuspid 
and  should  be  of  a  length  to  correspond  to  the  facet  which  is  to  be 
ground  on  that  cuspid.  As  this  cannot  always  be  known  in  advance, 
it  will  doubtless  be  necessary  to  try  the  teeth  in  position  and  adjust  the 
lengths  of  the  facets. 

Care  should  be  taken  not  to  grind  this  distal  facet  on  the  upper 
lateral  at  the  same  inclination  as  the  mesial  facet,  since  its  inclination 
should  correspond  in  all  directions  to  the  inclination  of  the  mesial  facet 
on  the  lower  cuspid.  It  must  be  borne  in  mind  that  this  distal  facet 
on  the  lateral  is  to  both  articulate  and  occlude  with  the  lower  cuspid. 

The  mesial  facet  on  each  upper  cuspid  will  be  of  the  general  form 
shown  in  Fig.  jSTo.  144,  but  it  will  be  governed  somewhat  by  the  relative 
widths  of  the  upper  and  lower  six  anteriors,  as  received  from  the  manu- 
facturer and  the  positions  in  which  the  teeth  are  set.  The  important 
point  is  that  the  tip  of  the  upper  cuspid  must  pass  through  the  inter- 
dental space  between  the  lower  cuspid  and  first  bicuspid  during  lateral 
movements,  and  that  the  upper  and  lower  cuspids  on  the  working  side 
should  both  occlude  and  articulate  as  long  as  the  dentures  are  in  contact. 

In  order  to  bring  about  these  relations,  it  will  probably  be  best 
to  grind  the  upper  incisors  and  cuspids  to  place,  and  then  the  lower 
cuspids,  governing  the  grinding  by  the  necessity  of  establishing  right 
relations  during  occlusion  and  articulation.  The  inclination  of  the 
facets  on  the  upper  cuspids  will  be  as  shown  in  the  drawings  of  the 
cuspids  in  Fig.  ]^o.  148,  and  the  relations  which  are  to  be  established 
are  shown  in  Fig.  l^o.  149.  If  the  teeth  are  all  in  position  before  the 
grinding  is  begun,  the  inclination  of  the  facets  on  the  upper  cuspids 

204 


GRIXDIXG  AXTEHIOK  TEETH  TO  FORM.— Continued 

may  be  determined  by  shaping  the  facets  so  that  a  match  laid  on  them, 
as  in  Fig.  Xo.  14G,  will  come  at  the  mesial  root  of  the  upper  first  molar, 
as  there  shown. 

The  difficulty  which  I  have  experienced  in  grinding  tliese  facets 
and  which  has  been  experienced  by  practically  all  whom  I  know,  is  an 
unwillingness  to  grind  the  mesial  facets  long  enough  on  the  upper 
cuspids.  There  seems  to  be  a  strange  unwillingness  to  do  this,  and 
even  after  careful  demonstration  I  have  found  men  leaving  these 
facets  so  short  that  the  point  of  the  upper  cuspid  passes  over  the 
lower  cuspid  in  articulation,  a  serious  fault. 

One  is  somewhat  deterred  also  by  the  fact  that  grinding  those 
cuspids  which  have  not  been  shaped  correctly,  often  spoils  the  appear- 
ance of  the  tooth,  and  sometimes  shortens  it  so  that  it  is  no  longer 
suital)le  for  the  case. 

It  is  not  usually  necessary  or  desiral)le  to  grind  facets  on  the 
cutting  edges  of  the  lower  incisors,  the  edges  they  present  l>eing  suffi- 
cient for  all  practical  purposes. 

It  is  however  essential  to  grind  facets  on  the  lower  cuspids,  a 
short  facet  on  the  mesial  of  each,  and  a  long  facet  on  the  distal,  as  shown 
in  Fig.  Xo.  143. 

The  short  mesial  facet  must  be  of  the  same  length  as  the  distal 
facet  (»n  the  opposing  upper  lateral,  so  that  when  the  teeth  are  occluded 
the  tip  of  the  lower  cuspid  shall  be  opposite  the  interdental  space  be- 
tween the  upper  lateral  and  cuspid.  Tliese  facets  must  be  of  such  in- 
clination that  the  lateral  will  not  be  forced  out  of  place  by  articula- 
tion with  the  cus])ids.  I  find  this  a  most  dangerous  point  for  a  contact 
which  dislodges  dentures  during  articulation. 

The  distal  facets  on  the  lower  cuspids  are  of  the  same  length  as 
the  mesial  facets  on  the  upper  cuspids,  so  that  the  distal  angle  of  each 
lower  cuspid  is  dii'octly  l)elow  or  slightly  mesial  to  tlie  tip  of  the  upper 
cuspid.  This  rcUition  will  be  slightly  affected  l>y  the  location  of  the 
rotation  points  if  The  Oysi  Adaptable  Articulator  is  used,  but  the 
distal  angle  of  the  lower  cuspid  does  not  often  come  distal  to  the  lip 
of  the  upper.  The  inclination  of  this  facet  must  he  coniplementarv  to 
that  on  the  opj)osiiig  facet  of  the  upper  cuspid,  as  shown  in  the  draw- 
ings of  these  teeth  in  Fig.  Xo.  148.  The  best  method  of  getting  the 
inclination  of  this  facet  is  to  place  the  upper  aiul  lowei'  cuspids  in 
position  and  grind  the  distal  facet  on  the  lowci-  so  that  it  is  parallel 
to  tlie  jru'sial  facet  of  tiu;  upjjei-  with  which  it  aiM  iculates. 


SETTIiq^G  UP  THE  BICUSPIDS  AND  MOLARS. 

Fiss.  Nos.  150  to  159  Inclusive. 


'■fa'- 


Prof.  Gysi's  methods  of  articulating  bicuspids  and  molars  are  so 
much  shorter  and  better  than  those  I  advocated  in  the  book  entitled 
"The  Mechanical  Side  of  Anatomical  Articulation"  that  I  have  given 
up  the  working  out  of  the  articulating  curves  and  now  follow  his  meth- 
ods, which  I  am  glad  to  present  here.  The  technic  is  rather  long  to 
describe  because  so  many  specifications  are  required,  but  is  really 
shorter  than  most  other  methods,  once  it  has  been  mastered.  These 
methods  are,  in  brief,  to  set  the  upper  bicuspids  and  molars  in  certain 
positions  against  the  flat  occlusal  surface  of  the  lower  trial  plate, 
establishing  the  curves  by  tilting  the  teeth  laterally;  to  set  the  lower 
teeth  to  occlusion  with  the  uppers  and  then  make  them  perfect  their 
own  articulation  by  a  method  which  he  calls  "automatic  articulation." 
To  employ  this  method,  he  sets  both  the  upper  and  lower  bicuspids  and 
molars  higher  than  they  are  to  be  in  the  finished  denture  and  makes 
them  adjust  each  other  by  pressure  as  they  are  closed  together. 

When  the  upper  and  lower  anteriors  are  set  and  waxed  firmly  to 
position,  open  the  bite  about  1.5  m.m.  (1/16  inch)  by  moving  the 
Incisor  Guide  Pin  downward  and  locking  there.  Set  the  upper  bicus- 
pids and  molars  of  both  sides  in  contact  with  the  lower  trial  plate,  as  in 
Fig.  1^0.  150.  Then  raise  the  bite  another  1.5  m.m.  and  set  the  lower 
bicuspids  and  molars  to  occlusion  with  the  uppers.  This  leaves  the 
upper  and  lower  anteriors  separated  3  m.m.  and  the  upper  and  lower 
bicuspids  and  molars  in  occlusion. 

The  arrangement  of  the  teeth  will  be  determined  in  large  part  by 
the  type  of  arch.  All  arches  may  be  described  under  three  headings, 
as  narrow,  medium  wide,  or  broad.  As  Dr.  Williams  showed  long 
ago,  the  form  of  the  arch  is  closely  parallel  to  that  of  the  face  just 
below  the  level  of  the  eyes,  and  it  is  neither  good  mechanics  nor  good 
esthetics  to  try  to  make  all  arches  conform  to  one  type. 

Illustrations  of  the  three  types  of  arches  are  shown  in  Figs.  ISTos. 
152,  153,  and  154.  Fig.  152  represents  the  medium  arch.  The 
lines  touching  the  mesio-buccal  ridges  of  the  first  molars,  the  buccal 
ridges  of  both  bicuspids  and  the  labial  ridges  of  the  cuspids  meet  at  the 
point  "C"  which  is  nearly  as  far  in  advance  of  the  point  "B"  as  the  point 
"B"  is  in  front  of  the  point  "A."  The  triangle  B-B-B  is  equilateral,  and 
so  is  the  small  triangle  in  dotted  lines,  with  its  apex  at  the  point  "A" 
and  its  other  termini  at  the  distal  angles  of  the  cuspids.  It  will  be  noted 
also  that  the  straight  lines  which  touch  the  distal  portions  of  the  buccal 
surface  of  the  first  molar  and  the  buccal  surfaces  of  the  second  molars 
are  nearly  parallel. 

In  arches  of  the  narrow  type.  Fig.  'No.  153,  the  arch  between  the 
cuspids  is  not  as  narrow  as  might  be  expected.  It  is,  if  anything, 
flatter  than  in  the  medium  arch.  The  bicuspids  and  molars  are  ar- 
ranged in  straighter  lines  and  more  directly  back  of  the  cuspids.  The 
lines  touching  the  cuspids,  bicuspids  and  molars  do  not  converge  at 

206 


Fig.   150. 

When  the  upper  and  lower  anteriors  have  been  arranged  at  the  desired  height  of  bite, 
the  articulator  should  be  opened  about  1.5  m.m.  (1-16  inch)  and  the  upper  bicuspids  and 
molars  on  both  sides  set  into  place. 

The  articulator  should  then  be  opened  another  1.5  m.m.  and  the  lower  bicuspids  and 
molars  of  both  sides  set  in  position  to  occlude  with  the  uppers. 

The  difference  of  3  m.m.  in  height  permits  the  use  of  Prof.  Gysi's  method  of  automatic 
articulation,  by  which   the  teeth   may  be  adjusteil   to  articulating   positions. 


Fig.  151. 

If  a   iiifce  of  cigar  box  be  sipiared  to  a  size  of  about  three  Inches,  it  will  be  found 
very  UHeful  In  determining  tlie  positions  of  the  teeth. 


207 


SETTIis^G  UP  THE  BICUSPIDS  AND  MOLARS— Contimied. 

the  point  ^'C"  but  farther  forward.  The  lines  touching  the  first  and 
second  molars  converge  slightly  more  than  the  similar  lines  in  the 
medium  arch.  The  base  of  the  equilateral  triangle  B-B-B  does  not 
terminate  in  the  buccal  grooves,  as  in  the  medium  arch,  but  extends  to 
the  buccal  surfaces  of  the  second  molars. 

In  arches  of  the  wide  type,  Fig.  ISTo.  154,  the  arrangement  of 
the  upper  anteriors  is  very  similar  to  that  in  the  medium  arches,  and 
the  positions  of  the  second  molars  are  almost  identical.  The  first 
molars  are  rotated  so  that  the  mesio-buccal  cusps  are  farther  from  the 
median  line  and  the  longitudinal  groove  is  more  nearly  straight  for- 
ward and  back.  The  bicuspids  are  not  so  directly  behind  the  cuspids, 
and  the  lines  touching  the  cuspids,  bicuspids  and  first  molars  converge 
before  they  reach  the  point  "C." 

If  the  trial  plates  have  been  carved  to  restore  the  fullness  desired 
in  the  patient's  face,  the  curves  of  the  bicuspid  and  molar  region  will 
probably  indicate  which  type  of  arch  the  case  presents. 

If  a  small  piece  of  wood,  preferably  cigar  box  wood,  be  cut  to 
the  form  of  a  square,  three  inches  on  a  side  as  in  Fig.  No.  151  will 
prove  very  useful  in  establishing  the  relations  indicated  by  the  several 
lines  in  Figs.  Nos.  152,  153,  151-. 

Having  determined  the  type  of  arch,  the  upper  bicuspids  and' 
molars  are  set  with  their  vertical  axes  in  the  lines  shown  in  Fig.  No. 
155.  The  buccal  cusp  of  the  upper  first  bicuspid  touches  the  occlusal 
surface  of  the  lower  trial  plate,  but  the  lingual  cusp  does  not  quite 
touch.  Both  cusps  of  the  upper  second  bicuspid  touch  the  wax.  Both 
lingual  cusps  of  the  upper  first  molar  touch  the  wax,  but  the  buccal 
cusps  are  elevated  about  a  millimeter  above  the  wax  and  begin  the 
compensating  curve  formed  by  the  buccal  cusps  of  both  upper  molars. 

The  lingual  cusps  of  the  upper  second  molars  are  in  contact  with 
the  opposing  trial  plate,  but  the  buccal  cusps  are  elevated  about  2  m.ni. 
above  the  wax.  They  continue  the  compensating  curve  which  the  buccal 
cusps  of  the  first  molars  began. 

It  is  necessary,  while  establishing  these  relations,  to  secure  such 
positions  of  the  teeth  over  the  ridges  as  will  give  the  dentures  maximum 
stability  and  efficiency.  This  can  be  done  best  by  keeping  the  teeth 
below  the  upper  alveolar  ridge,  after  the  manner  shown  in  the  upper 
illustration  of  Fig.  ISTo.  156.  Properly  articulated  dentures  are  not 
easily  dislodged  during  articulation,  even  if  the  teeth  are  outside  the 
ridge.  But  during  the  time  when  the  mouth  is  open  and  the  dentures 
do  not  support  each  other,  dentures  are  more  easily  dislodged  if  the 
upper  teeth  are  set  outside  the  ridge.  In  all  cases,  the  molars  and 
bicuspids  should  be  kept^as  nearly  in  line  with  the  ridges,  as  the  other 
conditions  of  the  case  permit.  If  the  trial  plates  were  formed  after  the 
manner  shown  in  Fig.  No.  156,  the  teeth  should  come  in  these  positions 
merely  by  setting  them  in  proper  relations  to  the  opposing  wax. 

208 


A 


Fig.   lo2 


Fig.   1.-..".. 


Fig.  154. 


Fig.  Nil.  l.K  represents  an  of(liis;il  view  (if  the  medium  arch  on  the  basis  of  Dr. 
Bouwill's  theory.  The  triangle  B — IV — B-  is  equal  sided.  It  will  be  noted  that  one  point 
rests  between  the  points  of  the  upper  incisors  and  the  other  points  at  the  distal  ends 
of  the  longitudinal  groove  on  the  occlusal  surfaces  of  the  upper  second  molars. 

The  outside  converging  lines  which  meet  at  the  point  "<_"'  touch  tlie  buccal  ridges  of 
the  cuspids,  the  bicuspids  and  the  mesio-buccal  ridges  of  the  first  molars.  The  distance 
from  the  point  "C"  to  the  point  "B"  is  nearly  equal  to  the  distance  from  "A"  to  "B." 

Fig.  No.  153  represents  the  narrow  arch  in  the  same  way.  The  equilateral  triangle 
no  longer  ends  in  the  longitudinal  groove  of  the  second  molars,  but  extends  outside  of  the 
disto-buccal  angles.  The  lines  which  touch  the  molars,  the  bicuspids  and  the  cuspids, 
do  not  meet  at  the  point  "('"  but  considerably  in  advance  of  it. 

Fig.  No.  154  represents  a  siiuilar  view  of  the  broad  arch.  This  arch  is  distinguished 
by  its  width  in  the  bicuspid  se<ti()n  rather  than  in  the  region  of  the  second  molars.  The 
posterior  ends  of  the  equilateral  triangle  end  about  where  they  did  in  the  medium  arch, 
but  the  bicuspids  set  so  much  farther  out  that  the  lines  which  touch  the  molars,  bicuspids 
anil  cuspids  converge  long  before  they   reach  the   point   "C." 


I'i;:.   l-'i."i. 

"I""  indicates  the  proper  vertical  position  of  tlic  upper  lirst  bicuspid  against  the 
occluHal  Hurface  of  the  lower  trial  plate,  "pa"  indicates  the  position  of  the  second  upper 
bicuspid.  ".M'"  Indicates  the  i)osltion  of  the  upper  first  molar  and  "M^"  the  position  of 
the   u|iiier   second   molar. 


200 


SETTING   UP   THE   BICUSPIDS   AND   MOLARS— Continued. 


Fig.  156. 


1 


Fig.  157. 

Diagrammatic  illnstratiou  of  good  and  false  relations  of  the  upper  posteriors  to  the 
ridge.  If  the  upper  molars  are  kept  in  the  line  from  the  crest  of  the  upper  ridge  to  the 
crest  of  the  lower  ridge,  the  dentures  will  be  more  stable  in  position. 

When  the  teeth  have  been  placed  in  these  positions,  the  relations 
may  be  tested  by  means  of  the  little  piece  of  squared  wood.  With  a 
pair  of  dividers,  the  terminations  of  the  triangle  here  marked  B-B-B 
may  be  located  as  guides  in  establishing  right  proportions  in  normal 
cases. 

When  the  upper  bicuspids  and  molars  have  been  set  in  the  eleva- 
tion of  1.5  m.m.  above  the  upper  anteriors,  the  articulator  is  opened 
1.5  m.m.  additional,  and  the  lower  bicuspids  and  molars  are  set  to 
occlusion  with  the  uppers,  and  both  sets  are  waxed  firmly  in  position. 
The  relations  of  the  teeth  are  established  as  accurately  as  possible  with- 
out making  lateral  movements  of  the  articulator  and  without  grinding 
the  teeth.  They  will  be  very  much  easier  to  establish  if  correctly 
formed  teeth  are  used.  Indeed,  unless  such  teeth  are  used,  the  steps 
which  are  to  follow  cannot  well  be  performed. 

The  teeth  are  now  more  accurately  adapted  by  a  process  which 
Prof.  Gysi  calls  ''automatic  articulation." 

210 


Fig.  158. 
By  means  of  the  piece  of  vigar  box,  tlie  degree  of  outwiird  inclination  given   to  any 
of  tbe  teetli  t-au  be  easily  seen,  and  botli  sides  can  be  k;ept  alike.     This  is  especially  nseful 
when,  for  any  reason,  the  trial  plate  has  been  taken  from  the  model. 


INCLINATION  OF  COMPENSATING 
CURVE    FOR   SHALLOW 
OVERBITE    OF 
ANTERIORS.  ■ 


OCCLUSAJ 


COMPENSATlNi 
FOR  OEFP  OVERI 
OF  ANTERIORS 
BJCCAL  *N0  LIMSOi 
CUSf.=^  iNCLUDEO, 


^^^^iiiH^ 


'^^^^>. 


'■<'^Suir^l''s 


%#itii^ 


Fig.  159. 

In  cases  where  tlie  iintcriors  e.xliibit  shallow  overbite,  the  compensating  cnrve  of  tlie 
upper  teeth  does  not  include  the  disto-lingual  cusps  of  the  upper  first  molars  or  the 
meslo-llngual  cusps  of  the  upper  second  molars.  Kut  in  cases  where  the  upper  anteriors 
exhibit  deep  overbite,  the  coniiiensating  curve  of  the  upi)er  teeth  lifts  the  disto-lingual 
cusps  of  the  u[)per  first  molars  and  the  mesio-lingual  cusps  of  the  second  molars  above 
the  oc<lnsal   plane. 


211 


AUTOMATIC  AllTIC UL ATIOK 
Fig.  ^^o.  160. 

This  is  a  process  of  making  the  teeth  adapt  themselves  to  exact 
positions  by  throwing  the  dentnres  into  lateral  occlnsion  and  pressing 
them  together  first  on  one  side  and  then  on  the  other.  It  can  be  put 
into  advantageous  execution  only  after  the  bicuspids  and  molars  have 
been  set  at  higher  than  ordinary  levels,  as  described  on  page  206  to  210 
inclusive. 

The  Incisor  Guide  Pin  is  raised  about  1  m.m.  out  of  contact  with 
the  Inclined  Plane  and  the  set  screw  tightened.  The  wax  about  the 
necks  of  the  teeth  is  slightly  warmed  so  that  the  teeth  can  be  moved 
by  pressure.  The  articulator  is  opened  and  moved  into  lateral  occlu- 
sion on  one  side  and  closed  with  the  upper  and  lower  buccal  cusps  of 
that  side  interdigitated.     Slight  pressure  is  exerted. 

The  denture  is  then  opened  and  returned  to  a  position  of  central 
occlusion  and  pressure  is  exerted  in  that  relation  of  the  dentures.  The 
wax  about  the  teeth  is  kept  in  such  a  state  of  softness  by  occasional 
warming,  as  permits  the  adaptations  of  one  set  of  teeth  by  the  other. 
The  wax  can  be  warmed  for  this  process  best  by  applying  the  heat  of 
a  small  flame  to  the  occlusal  surfaces  of  the  bicuspids  and  molars,  and 
letting  it  reach  the  wax  through  the  porcelain. 

The  dentures  are  now  carried  into  a  position  of  lateral  occlusion 
on  the  side  opposite  that  first  occluded,  and  pressure  is  made  with  the 
buccal  cusps  interdigitated.  They  are  then  returned  to  the  position 
of  central  occlusion  and  pressed  together. 

By  this  time  it  will  be  necessary  to  lift  the  Incisor  Guide  Pin  an- 
other millimeter  out  of  contact  with  the  Inclined  Plane  and  tighten 
the  set  screw.  The  former  steps  are  then  repeated  until  the  pin  comes 
into  contact  with  the  Incisor  Guide  Incline.  A  third  lifting  of  the  pin 
will  bring  the  upper  and  lower  anteriors  into  articulating  relations. 

A  few  points  require  especial  attention  during  this  process.  First 
of  all,  the  teeth  must  be  mounted  in  a  wax  which  holds  them  against 
sliding.  Some  waxes  defeat  the  efforts  to  automatically  articulate  den- 
tures because  the  teeth  slide  so  that  it  is  impossible  to  keep  them  in 
position  while  exerting  pressure  in  lateral  occlusion.  I  have  failed 
with  several  waxes  but  have  had  good  results  with  Dentsply  Baseplate 
wax. 

The  teeth  must  be  held  on  the  buccal  surface  against  the  tendency 
to  slide  which  results  from  pressure  in  lateral  occlusion.  If  the  thumbs 
are  placed  against  the  buccal  surfaces  of  the  bicuspids  and  molars  dur- 
ing the  time  of  pressure,  slipping  can  be  prevented.  Fig.  No.  161 
shows  how  Prof.  Gysi  holds  dentures  for  automatic  articulation. 

jSTo  sliding  movements  should  be  made  during  this  operation.  The 
teeth  are  probably  not  accurately  adapted,  and  such  movements  will 
merely  dislodge  them. 

212 


Kit,'.   lilO. 

In    tlif   Mt  '■oliiinii    side   views  of  I  he   scvcriil    pusitions   in   imtoiiiatii-   arti<uhiti(in.      In 
the  rljilit  <'i>lnnin,   rear  views  of  tlie  same   positions. 


2J3 


AUTOMATIC    ARTICULATION^— Continued. 


Fig.  161. 

Prof.    Gysi    holding    the    teeth    from    sliding    during    the    movements    of    automatic 
articulation. 


If  automatic  articulation  is  properly  carried  out  it  establishes 
in  a  few  moments  relations  which  most  of  us  have  spent  hours  seeking 
to  establish  by  other  methods.  It  adjusts  the  inclinations  of  the 
several  teeth  to  the  movements  of  the  mandible  of  the  articulator.  In 
cases  where  the  Gysi  Adaptable  Articulator  is  used,  that  means  to  the 
movements  peculiar  to  the  patient. 

It  determines  the  steepness  of  the  compensating  and  lateral  curves 
better  than  it  can  be  done  by  any  other  method.  In  cases  where  the 
overbite  of  the  incisors  is  shallow,  this  curve  will  include  only  the 
buccal  cusps  of  the  first  and  second  molars  and  the  disto-lingual  cusps 
of  the  upper  second  molars.  In  cases  where  the  overbite  of  the  incisors 
is  deep,  this  curve  will  affect  the  lingual  cusps  of  both  molars  as  can 
be  seen  from  a  study  of  Fig.  No.  159. 

Automatic  articulation  also  rotates  the  teeth  on  their  vertical  axes 
to  afford  the  most  satisfactory  relations  with  the  opposing  teeth. 

The  intelligent  dentist  who  masters  the  slight  technic  of  this  oper- 
ation, will  appreciate  more  than  ever  before  the  skill  with  which  Prof. 
Gysi  has  formed  Trubyte  bicuspids  and  molars,  because  with  them  re- 
lations may  be  very  quickly  and  satisfactorily  established.  With  some 
forms  of  teeth  this  method  is  ineffectual  because  the  teeth  are  not 
shaped  to  make  it  effective. 

214 


GRIXDIXG   THE   TEETH   TO   EIXISHED   ARTICULATION 

When  the  process  of  automatic  articuhitioii  has  been  completed, 
the  teeth  should  be  in  the  most  advantageous  positions  which  can  be 
secured  by  moving  each  tooth  as  a  whole.  The  articulation  must  be 
completed  hx  grinding. 

There  seems  to  be  a  general  impression  among  dentists  that  the 
need  for  grinding  is  evidence  that  the  teeth  are  not  correctly  formed, 
and  that  if  they  were  rightly  formed  no  grinding  would  be  needed. 
Such  an  idea  is  a  mistake. 

If  teeth  require  to  be  extensively  ground  to  permit  articulation, 
it  is  evidence  that  they  w^ere  not  rightly  formed  or  not  rightly  selected 
or  placed.  But  grinding  has  its  proper  and  important  place  in  the 
scheme  of  articulation,  and  dentures  which  have  been  properly  ground 
are  better  than  those  which  have  not. 

P>ut  little  if  any  grinding  should  be  necessary  with  a  stone.  Occa- 
sionally a  little  porcelain  will  flow  out  of  its  appointed  place  and  will 
need  taking  down  with  a  stone.  Occasionally  the  conditions  of  the 
case  will  require  minor  adjustments  of  widths  with  a  stone.  But  no 
reshapinu'  of  the  teeth  or  other  extensive  changes  should  l)e  necessary. 
The  articulation  of  the  dentures  is  finished  by  grinding  the  sets 
tou'ether  with  a  paste  of  carborundum  powder  and  glycerine  between 
the  cutting  edges  and  occlusal  surfaces.  The  dentures  should  be  held 
in  contact\vith  light  but  firm  pressure  and  made  to  perforni  the  lateral 
movements  of  mastication.  This  may  be  continued  until  the  right 
relations  are  established  to  the  dentist's  satisfaction,  and  the  proper 
facets  have  been  perfected  on  the  anteriors  and  formed  on  the  bicuspids 
and  molars.     This  should  not  require  more  than  20  minutes. 

The  formation  of  these  facets  on  the  bicuspids  and  molars  is  very 
important  to  the  efficiency  of  the  dentures,  and  they  cannot  be  formed 
in  any  other  manner  than  by  grinding  the  sets  together  in  this  manner. 
It  may  be  helpful  to  some  to  understand  just  why  these  facets 
cannot  l>e  formed  by  the  manufacturer  and  why  they  mnst  be  formed 
by  the  dentist.  They  cannot  be  formed  by  the  manufacturer,  because 
they  cannot  be  formed  at  all  until  the  teeth  are  articulated.  The  utmost 
that  the  manufacturer  can  do  is  to  furnish  teeth  properly  formed  to 
receive  the  facets.  That  requires  the  most  extensive  knowledge  of 
articulation  and  the  most  advanced  methods  of  tooth  formation. 

The  facets  cannot  be  formed  until  the  teeth  are  articulated  because 
tlieir  location  and  extent  are  determined  by  the  positions  of  the  teeth 
and  no  one  can  foresee  those  positions.  The  facets  have  little  value  if 
the  facets  of  one  set  are  not  complementary  to  those  of  the  other  set, 
so  that  the  edges,  when  passing,  cut  up  fibres  and  the  surfaces  roll  the 
cells  and  smash  the  cell  walls. 

The  grinding  removes  the  glaze  from  the  facets  and  leaves  it  on 
the  other  portions  of  the  occlusal  surfaces  so  that  food  shall  not  lodge 
there. 

215 


Fig.  102. 

Photograph  showing  upper  and  lower  dentures  in  a  practical  case  after  they  had 
been  ground  by  automatic  articulation  and  the  facets  had  been  perfected  on  the  cutting 
edges  of  the  anterior  teeth  and  formed  on  the  occlusal  surfaces  of  the  biciispids  and 
molars,  by  rubbing  the  sets  together  in  lateral  movements  with  a  paste  of  carborundum 
^d    glycerine    between    them. 

The  facets  indicate  clearly  what  portions  of  each  tooth  are  in  articulation  with  the 
opposing  tooth  during  movements  to  both  sides.  By  far  the  larger  portion  of  each 
surface  never  enters  into  articulation  when  the  teeth  are  properly  formed.  The  portions 
which  articulate  in  a  single  lateral  movement  are  relatively  small,  since  it  proved  impossi- 
ble to  here  separate  the  facets  engaged  in  one  movement  only,  and  more  than  one  facet  is 
here  shown  in  nearly   every   ground   section. 

While  the  margins  of  the  facets  are  not  sharp  in  the  way  a  knife  is,  they  are 
clearly  differentiated  from  the  rest  of  the  tooth  surface  and  are  sharp  enough  to  cut 
food   when    drawn   across    opposing   facets. 

Enough  power  can  be  transmitted  through  dentures  to  make  teeth  formed  and 
articulated  in  this  way  effective  in  mastication,  when  the  ordinary  forms  of  teeth 
would    be    wholly    ineffective. 


216 


Fig.  103. 


How  properly  formed  teeth  masticate  food.  This  is  from  a 
photograpli  of  a  sheet  of  modelling  compound  into  which  properly 
articulated  sets  of  Trubyte  teeth  were  closed.  The  rather  wide  and 
shadowy  outline  shows  where  the  crowns  of  the  teeth  l)it  into  the  com- 
pound. The  smaller,  lighter  areas  show  where  the  teeth  bit  practically 
through  the  compound. 

It  will  be  noted  that  the  teeth  nowhere  bit  through  in  a  large  area, 
but  at  all  the  points  of  closest  opposition  of  the  teeth  are  smalL  It 
will  be  noted  also  that  each  spot  of  close  approximation  resembles 
somewhat  a  short  knife  blade,  blunt  when  compared  to  a  real  knife,  but 
sharp  when  compared  to  the  opposed  areas  of  artificial  teeth  in  the  past. 

Xo  lateral  movements  were  made  in  this  case,  but  it  is  easy  to  see 
that  with  .so  many  small,  closely  opposed  areas,  the  lateral  movement 
of  the  teeth  would  be  very  efr'ective  in  masticating  the  food. 

The  relatively  small  power  whicli  can  be  transmitted  through 
artificial  dentures  can  make  these  small  areas  effective,  in  cutting  up 
the  fibres  and  in  smashing  the  cell  walls  so  that  th(;  contents  of  the 
cells  may  be  insalivated. 


217 


TRUBYTE  MOLAE  BLOCKS. 
Fig.  No.  164. 

Prof.  Gysi  has  perfected  an  improvement  in  bicuspids  and  molars 
which  goes  farther  toward  simplifying  articulation  in  full  dentures 
than  any  other  one  thing  of  which  I  know.  He  has  combined  the  four 
bicuspids  and  molars  of  one  side  of  one  jaw  into  a  solid  block  the 
occlusal  surface  of  which  presents  the  curves  essential  to  articulation. 
There  are  two  of  these  blocks  for  the  upper  denture  and  two  for  the 
lower. 

The  curves  of  the  occlusal  surfaces  are  designed  for  the  average 
adaptations,  as  exhibited  in  The  Simplex  Articulator,  They  may  be 
arranged  for  any  required  depth  of  curve  by  merely  elevating  the  upper 
second  molars  to  the  desired  extent. 

The  upper  block  is  properly  placed  by  setting  the  buccal  cusp  of 
the  upper  first  bicuspid  and  both  cusps  of  the  second  bicuspid  in  con- 
tact with  the  flat  occlusal  surface  of  the  lower  trial  plate. 

The  advantages  attending  the  use  of  these  blocks  are  as  follows : 

The  teeth  can  be  set  in  about  one-fourth  of  the  time  required  to 
set  the  single  teeth. 

J^o  curves  need  be  worked  out  even  by  the  eye.  When  the  bicus- 
pid cusps  touch,  as  described  above,  the  upper  block  is  in  correct  posi- 
tion for  automatic  articulation. 

The  position  of  each  of  the  teeth  in  the  block  is  fixed  as  regards 
the  other  posteriors  on  the  same  side. 

The  lower  blocks  go  to  definite  places,  and  require  only  grinding 
against  the  uppers  to  perfect  the  articulation. 

The  teeth  do  not  change  positions  during  vulcanization. 

The  hold  of  each  block  on  the  plate  is  very  strong. 

The  interdental  spaces  on  the  lingual  are  filled  with  porcelain 
and  make  a  fine  finish  for  the  tongue.  The  buccal  sides  appear  as 
plain  teeth,  that  is,  there  is  no  pink  porcelain  gum. 

The  moulds  are  the  same  as  in  the  plain  teeth.  They  present 
the  same  deep  fossse  and  sulci,  the  same  high  cusps  and  the  same  shal- 
low bite. 

I  believe  these  blocks  will  become  very  popular. 


2J8 


Fig.  104. 
Trubyte    Molar   Blocks. 


219 


WAXING  PLATES  TO  FACILITATE  PRONUNCIATION. 

Fig.  No.  165. 

Try  the  waxed  up  dentures  in  the  patient's  mouth.  Have  the 
patient  read  aloud  and  watch  the  mouth  for  length  of  teeth,  fulness  of 
lips,  etc. 

If  the  upper  plate  is  hollowed  behind  the  upper  incisors  as  shown 
on  the  left  in  I'igure  1G5,  the  patient  will  have  difficulty  in  pronouncing 
words  containing  s,  st,  th,  ch,  j,  x,  etc.,  such  as  "Peace  satisfies  the  soul." 


Fig.  105. 

The  anterior  portion  of  the  natural  vault  is  convex  behind  the  upper 
incisors  and  facilitates  clear  pronunciation.  This  form  can  be  repro- 
duced by  waxing  the  upper  denture  to  the  form  shown  at  the  right  in 
Figure  165. 

INVEST L\G  THE  BICUSPIDS  AND  MOLAPtS. 

A  fine  articulation  is  sometimes  destroyed  hy  a  tooth  changing 
place  during  vulcanizing.  The  simplest  way  to  prevent  this  is  to  use 
the  ]\lo]ar  Blocks,  which  are  not  likely  to  change. 

If  single  teeth  are  used,  the  danger  of  change  in  position  can  l)e 
reduced  to  a  minimum  by  keeping  on  hand  a  supply  of  sheet  copper 
such  as  tinners  use  for  water  conductors.  When  the  teeth  are  ready 
to  flask,  mal:c  a  trough  of  this  copper,  the  bottom  of  which  will  lie  along 
the  occlusal  surfaces  of  the  bicuspids  and  molars,  and  a  wall  of  which 
will  extend  up  along  the  buccal  surfaces.  Fill  this  with  Spence's 
Plaster,  mixed  thin  enough  to  permit  tapping  it  down  to  place  when 
inverted  on  the  teeth.  Invert  on  the  teeth  and  tap  down  to  touch  all 
the  occlusal  surfaces.  Be  careful  not  to  leave  any  Spence's  plaster  on 
the  wax. 

Invest  as  usual.     The  teeth  should  not  change  positions. 

ARTICULATING  THE  VULCANIZED  DENTURES. 

The  vulcanized  dentures  should  be  articulated  in  the  mouth  by 
means  of  articulation  paper,  or  double  faced  carbon  paper,  or  ordinary 
carbon  paper  doubled. 

The  patient  should  be  instructed  to  close  the  mouth  in  the  position 
of  central  occlusion  and  make  slight  rubbing  movements.  Points  of 
undue  prominence  will  be  marked  on  both  upper  and  lower  teeth. 

To  remove  such  spots,  grind  only  the  one  that  is  out  of  contact 
during  centred  occlusion.  If  the  other  is  ground,  it  destroys  the 
occlusion. 


220 


Tl;i-   liiiiil  result.     'I'fctli   liiirininiiuiis  in    f<ini),  size  niul   color,   stable  in    position,    and 
efl!'i<-ni. 


221 


PART   VIII. 


Illustrations  And  Descriptions 

Of  Teeth 
And  Tables  Of  Dimensions 


GEN^ERAL   lA^FORMATION   CONCERNING   FORMS    AND 

MARKINGS. 

The  forms  in  Trubjte  teeth  are  comprised  iu  three  classes,  each 
class  comprising  the  modifications  of  one  typal  form. 

Class  I  comprises  all  modifications  of  the  square  type. 

Class  II  comprises  all  modifications  of  the  tapering  type. 

Class  III  comprises  all  modifications  of  the  ovoid  type. 


Each  modification  is  represented  by  a  form,  and  each  form  is 
produced  in  a  series  of  graded  sizes  suited  to  the  characteristics  of  that 
form.  Each  size  of  each  form  constitutes  a  separate  mould.  Each 
mould  is  marked  with  the  number  of  the  form  and  with  a  letter  indi- 
cating the  size. 

Difi'erent  letters  are  used  to  indicate  sizes  in  the  dift'erent  classes. 
In  Class  I  the  letters  are  C-D-E-F-H.  In  Class  II  the  letters  are 
L-]^I-N-P-R.     In  Class  III  they  are  T-U-W-X-Y. 

The  number  and  letter  should  always  be  given.  It  is  then  not 
necessary  to  name  the  Class,  since  the  same  letters  do  not  appear  in  two 
classes. 


There  are  five  forms  in  Class  I,  representing  five  modifications  of 
the  long  square  form.  They  are  numbered  l-2-3-4:-5,  and  the  sizes  are 
IC-ID,  etc.,  and  2C-2I),  etc.  Outlines  of  the  forms  in  this  class  are 
shown  on  page  85. 


There  are  four  forms  in  Class  II,  representing  four  modifications 
of  the  tapering  form.  They  are  numbered  1-2-3-4,  and  the  sizes  are 
IL-lM,  etc.,  2L-2^r,  etc.  Outlines  of  the  forms  in  this  class  are  shown 
on  page  87. 


There  are  four  forms  in  Class  III,  representing  four  modifications 
of  the  ovoid  form.  They  are  numbered  1-2-3-4,  and  the  sizes  are 
IT-IU,  etc,  2T-2U,  etc.  Outlines  of  this  form  are  shown  on  page  89, 
l)iit  th(!  letters  indic;it  iiii:'  sizes  sliould  Ik'  T-TT-W-X-Y. 


At  the  time  n\'  ilic  piibliciil  ion  of  ibis  book,  ( 'biss  111  forms  are 
not  far  enough  coni[)let('d  to  pcsmiit  otlering  tliem  to  tlie  profession,  1)ut 
spaces  arc  provided  toj-  tilling  in  tluiir  dim(!nsions  when  they  appear. 


225 


FORAt  I— Class  I. 

This  is  the  long  modification  of  the  Square  Type,  in  which  the 
length  of  the  lahial  surface  of  the  upper  central,  exclusive  of  collar, 
markedly  exceeds  the  width. 

The  upper  centrals  and  laterals  are  distinguished  b}^  nearly  paral- 
lel sides  for  a  considerable  distance  upward  from  the  incisal  edges,  and 
by  rather  flat  approximal  curves  and  wide  necks.  These  curves  combine 
to  give  the  teeth  a  generally  square  appearance,  though  the  severe 
typal  form  has  been  so  far  modified  that  the  angularity  and  rudeness 
are  lost. 

The  upper  cuspids  present  flat  curves  on  the  mesial  surfaces,  but 
pronounced  curvatures  of  the  distal  surface.  The  shoulders  of  these 
cuspids  are  set  well  forward,  enabling  the  dentist  to  hide  the  bicuspids, 
and  secure  pleasing  effects.  The  points  of  the  cuspids  are  cut  well  back 
to  facilitate  articulation  with  the  lower  cuspids  with  a  minimum  of 
grinding. 

The  collars  of  the  upper  and  lower  anteriors  are  fairly  deep,  per- 
mitting the  dentist  to  imitate  recession  of  the  gimis. 

The  lower  incisors  are  distinguishable  from  the  lower  incisors  of 
the  past,  by  retaining  the  character  of  the  uppers.  The  approximal 
surfaces  are  nearly  parallel  for  a  short  distance  downward  from  the 
incisal  edge,  then  curve  inward  to  medium  wide  necks.  The  mesial  sur- 
faces present  convex  curves,  while  the  distal  surfaces  exhil)it  distinct 
compound  curves  which  greatly  increase  the  beauty  of  the  teeth. 

The  lower  cuspids  carry  out  the  character  seen  in  the  upper  cuspids 
and  have  their  shoulders  well  to  the  mesial.  This  will  greatly  assist 
in  building  up  the  lower  cuspid  eminences. 

The  upper  and  lower  anterior  teeth  are  shaded  as  descril)ed  on  page 
113.     Both  sets  present  natural  enamel  markings. 

The  upper  central  in  each  shade  is  shaded  like  the  sample  tooth 
on  the  Twentieth  Century  shade  ring,  and  no  other  colors  appear  in 
the  teeth. 

Indicatioxs.  Teeth  of  this  form  are  indicated  in  faces  which 
are  much  longer  than  they  are  wide,  and  which  exhibit  nearly  parallel 
sides  and  chins  of  full  medium  width  or  more.  Such  faces  are  com- 
mon. Many  faces  lie  on  the  border  line  between  this  form  and  Form 
IT  in  Class  I,  and  also  between  this  form  and  Form  I  in  Class  IT. 


226 


Dimensions    of    Trubyte     Teeth 


CLASS  I 
MODIFICATIONS  OF  THE  SQUARE    FYPE 

FIVE  FORMS  IN   GRADED  SIZES 


WHKX  DIMENSIONS  AKK  NoT  CIVKN  Tin-:  SI/.KS  .A.KK  IN   I'KHrAKATK  )N. 

Ai.i,  i)imp;nsi()Ns  akk  in  Mii.i.niKTKKs. 

Similar  dimensions  in  plain   vulcanite  pin  teeth;    combination  sets  with  individual  diatoric 
posteriors,  and  combination  sets  with  molar  blocks. 

FORM  1.    The  Long  Modification  of  the  Square  Type. 


UPPERS 


MoiiUl 
No. 

I^englh 

Central 

Without  Collar 

Width 

6  anteriors 
Set  up 

width 

iMlll     14 

Set  up 

Coinbine<l 

Bite  and  Shut 

of  Central 

width  of 
Central 

IC 

ID 

9.75 

42  43 

103. 

8. 

7. 

IE 

10.25 

45. 

108. 

9. 

7."> 

IF 

10.75 

46  47 

109-110 

9.5 

8. 

IH 

11.50 

51. 

123  124 

9.5 

8.5 

LOWERS 

Mould 
No. 

I.enjrth 

Central 

Without  Collar 

width 

<i  anteriors 
.Set  up 

width 
I-iilI     14 
Set  up 

Couibinetl 

Bite  and  Shut 

of  Central 

width 

?"our 

lucisoi 

IC 

ID 

9. 

32.5 

102. 

9. 

21. 

IK 

9. 

36. 

104. 

9. 

22.5 

IF 

9.5 

36. 

106. 

9. 

2:5. 

IH 

10  25 

40. 

115. 

9.5 

25. 

227 


FOKM  2— CLASS  I. 

This  is  the  medium  long  modification  of  the  Square  Form,  in 
which  the  length  of  the  labial  surface  of  the  upper  centrals,  exclusive 
of  collar,  considerably  exceeds  the  width  of  that  surface,  but  not  to 
such  a  degree  as  in  Form  I. 

The  approximal  surfaces  of  the  upper  centrals  and  laterals  are  not 
parallel  quite  so  far  upward  from  the  incisal  edge,  as  in  Form  I,  and 
because  of  the  shortness  of  the  teeth,  the  approximal  curves  seem  more 
rounding,  especially  in  the  small  sizes.     The  necks  are  medium  wide. 

The  upper  cuspids  carry  out  very  well  indeed,  the  character  of  the 
centrals  and  laterals.  The  shoulders  are  thrown  well  to  the  mesial, 
and  the  cutting  edges  are  cut  back  to  facilitate  articulation  with  the 
lower  teeth. 

The  lower  incisors  have  the  character  first  seen  in  the  lower  in- 
cisors of  Form  I,  the  convex  mesial  surfaces  and  the  compound  curves 
on  the  distal  surfaces.  The  labial  surfaces  of  these  teeth  stand  well 
forward  from  the  collars,  enabling  the  dentist  to  finish  the  vulcanite  for 
fine  eft'ects. 

Both  the  upper  and  lower  sets  are  shaded  as  described  in  the  fore- 
going pages.  Both  sets  present  natural  enamel  markings  on  the  labial 
surfaces. 

Indications.  The  teeth  of  this  form  are  indicated  in  faces 
slightly  longer  than  they  are  wide,  with  fairly  straight  sides  and  medium 
wide  chins.  Such  faces  are  very  common  and  the  various  sizes  of  this 
form  will  find  extensive  use. 

Many  faces  lie  in  the  border  land  between  this  form  and  Form  T 
in  this  class,  and  also  between  this  form  and  Form  II  in  Class  II.  In 
many  cases  a  mould  from  either  form  may  be  suitable.  This  increases 
the  availability  of  the  moulds  by  affording  suitable  teeth  of  other  di- 
mensions. 


228 


CLASS  I. 
FORM  2 — Medium  Long.  Square. 


TRUBYTE   FORM  2    CLASS  I 
SIZES  AS  MOULDS  2C-2  D-2E-2F-2H 


#iff%^ 


UPPERS 


Mould 
No. 

Length 

Central 

Without  Collar 

Width 

6  anteriors 

Setup 

Width 
Full  14 
Set  up 

Combined 

Bite  and  Shut 

of  Central 

Width  of 
Central 

2  C 

8.50 

42-43 

102-103 

8. 

7. 

2  D 

9.25 

44 

103 

8.5 

7.5 

2  E 

10. 

46-47 

108-109 

9.25 

8. 

2  F 

10.75 

48-49 

110-111 

9.5 

8.25 

2  H 

LOWERS 


.Mould 

Length 

Width 

width 

Combined 

width 

N'o 

Central 

b  anterior.s 

iMlll   U 

Bite  and  Shut 

l'"our 

Without  Collar 

Set  up 

Set  up 

of  Central 

Incisors 

2  C 

8.5 

33,. 

100 

7.5 

20. 

2  D 

9. 

34. 

101 

9. 

21.5 

2  E 

9. 

36.5 

106 

9. 

23. 

2  F 

10. 

37. 

106 

9.5 

23.5 

2  If 

229 


....        .     FOKM  3— CLASS  I. 

This  is  the  short  modification  of  the  Square.  Type,  in  which  the 
length  of  tlie  hibial  surfaces  of  tlie  upper  centrals,  exclusive  of  collar, 
slightly  exceeds  the  width. 

The  approxinial  surfaces  of  the  upper  centrals  are,  in  general, 
nearly  parallel  throughout  a  considerable  portion  of  the  length  of  the 
tooth,  but  the  sides  are  so  delicately  curved  as  to  take  away  any  appear- 
ance of  blockiness  which  might  otherwise  result.  The  necks  are  wide 
and  the  interdental  spaces  small.  The  sides  of  the  upper  laterals  are 
not  quite  so  nearly  parallel  as  those  in  the  centrals  but  the  generally 
square  character  is  well  carried  out.  The  cuspids  are  excellently  suited 
to  the  centrals  and  laterals,  the  mesial  approximal  surfaces  being 
strongly  convex,  the  shoulders  prominent  and  well  to  the  mesial,  and  the 
distal  angles  prominent. 

The  lower  incisors  appear  more  nearly  square  than  in  Forms  I 
and  II  but  they  present  the  same  convex  curves  on  the  mesial  approximal 
surfaces  and  somewhat  of  the  same  double  curve  on  the  distal  ap- 
proximal surfaces.  They  are  admirably  suited  in  character  to  the  upper 
anteriors.  The  lower  cuspids  are  very  much  like  the  uppers  in  char- 
acter, except  that  the  distal  angles  are  not  so  prominent. 

Both  the  upper  and  lower  sets  are  shaded  as  described  in  the  fore- 
going pages.     They  present  the  enamel  markings  on  the  labial  surfaces. 

Indicatiojs^s.  The  teeth  of  this  form  are  suited  for  faces  which 
are  nearly  as  wide  as  tliey  are  long,  and  which  present  nearly  parallel 
sides  with  flat  curves  and  wide  chins.  Such  faces  sometimes  present 
in  rather  large  sizes  but  it  is  not  believed  that  teeth  of  a  size  larger  than 
3D  will  be  required  for  any  ordinary  case. 


230 


CLASS  I. 
FORM  3— Short  Souare. 


UPPERS 


Mould 
No. 

Length 

Central 

Without  Collar 

Width 

6  anteriors 

Set  up 

Width 
Full  14 
Setup 

Combined 

Bite  and  Shut 

of  Central 

width  of 
Central 

3  C                    8. 
3  D          '          8.75 

3  E 

1 

44-45 
45-46 

105-106 
108-109 

8. 

8. 

7.75 
8. 

LOWERS 


Mould 

No. 

Length 

Central 

Without  Collar 

Width 

6  anterior.s 

Set  up 

Width 
Full  11 
Set  up 

Combined 

Bite  and  Shut 

of  Central 

Width 
Four 

Incisor.s 

3  C 
3  D 
3  E 

7.75 

8.75 

35. 
36. 

103. 

106. 

8. 
8.50 

23. 

23. 

231 


FORM  4— CLASS  I. 

While  the  majority  of  faces  of  the  square  type  present  one  of  the 
modifications  exhibited  in  Forms  1,  2,  3  or  5,  a  feminine  face  some- 
times presents  which  differs  from  these  in  presenting  a  square  form 
which  is  somewhat  softened  by  greater  delicacy  of  outline  and  yet  does 
not  present  the  type  of  chin  seen  in  oval  faces. 

To  permit  artistic  restorations  in  faces  of  this  modification. 
Form  4  has  been  provided.  It  is  distinguished  from  Forms  1,  2,  3  by 
greater  convexity  of  the  approximal  surfaces,  especially  on  the  distal,  in- 
cluding a  greater  rounding  away  of  the  distal  incisal  angles.  The  upper 
laterals  are  delicate  and  beautiful  in  form,  and  the  upper  cuspids  are 
rather  small  as  compared  with  the  centrals,  being  intended  to  produce 
the  impression  of  softness  and  beauty  rather  than  of  the  rugged  strength 
which  characterizes  most  of  the  square  forms. 

The  collars  of  both  upper  and  lower  anteriors  are  fairly  deep  and 
permit  the  dentist  to  establish  imitations  of  slightly  receding  gums. 

The  lower  incisors  are  small  and  dainty  but  are  full  of  character. 
The  mesial  approximal  surfaces  are  gently  rounding,  and  the  distal 
approximal  surfaces  present  the  compound  curves  seen  in  this  type 
of  tooth.  The  lower  cuspids  are  small  and  carry  out  the  impression 
of  daintiness  given  by  the  upper  cuspids. 

I:\^DiCATioNS.  For  feminine  faces  in  which  the  cheek  curves  are 
more  rounding  than  in  the  stronger  forms  illustrated  on  page  Y9,  and 
where  the  face  has  a  rather  dainty  appearance,  but  the  chin  is  fairly 
wide.  Such  faces  are  often  small,  and  the  sizes  4C  and  4D  will  be 
found  verv  useful  in  this  mould. 


232 


CLASS  I. 
FORM  4 — The  P'eminink   Modification  of  The  Square  Type. 


UPPERS 


Mould                     Length                   Width                    Width 

jjo                          Central                6  anteriors                 Full  14 

Without  Collar            Set  up                    Set  up 

Combined               ^idlh  of 
BiteandShut             Cential 
of  Central 

4  C 

4  D                        9.                         40.                       97. 

4  E 

4  F                     10.0                     45.                    107. 

1 

8. 
9. 

7. 
8. 

LOWERS 


.Mould 
No. 

Length 

Central 

Without  Collar 

Width 
b  anteriors 

Set  up 

width 
Full  14 
Set  up 

Combined 

Bite  and  Shut 

of  Central 

Width 

Four 

Incisors 

4  C 

4  J) 

8. 

29. 

93. 

8. 

18. 

4  i<: 

4  F 

9. 

33. 

102-103 

S. 

21. 

23.? 


FOKM  5  — CLASS  I. 

This  is  the  oval  modiiication  of  the  square  type,  formed  by  a 
slight  modification  of  the  curves  of  the  mesial  and  distal  approximal 
sides.  Where  the  sides  were  relatively  straight  in  Forms  1,  2,  3,  and 
rounded  into  the  necks  and  incisal  edges  by  short  curves,  the  approximal 
curves  in  the  oval  form  converge  more  gradually,  forming  narrower 
necks  and  leaving  larger  interdental  spaces.  The  widest  part  of  the 
upper  centrals  is  a  little  above  the  incisal  edge,  and  the  mesial  and 
distal  incisal  angles  are  more  rounded  than  in  the  first  three  forms  in 
this  class. 

The  upper  laterals  present  quite  dift'erent  characteristics,  showing 
much  more  of  a  compound  curve  on  the  mesial,  and  a  marked  rounding 
away  of  the  distal  incisal  angle.  Indeed,  in  this  form,  the  upper 
laterals  contribute  a  great  deal  to  the  appearance  which  separates  the 
oval  form  from  the  more  severely  square  forms. 

The  upper  cuspids  are  very  much  of  the  same  character  as  the 
laterals  and  help  to  differentiate  these  anteriors  from  any  other  square 
form.  The  mesial  approximal  surfaces  show  pronounced  convex  curves 
with  a  typical  rounding  away  at  the  neck.  The  distal  surfaces  present 
very  noticeable  compound  curves. 

The  mesial  approximal  surfaces  of  the  lower  incisors  present  the 
convex  curves  of  the  same  character  as  those  seen  in  the  upper  anteriors, 
and  strong  compound  curves  on  the  distal  sides.  The  necks  are  wide 
and  the  interdental  spaces  small.  The  lower  cuspids  present  only  a 
trace  of  the  rounding  away  of  the  mesial  surface  seen  in  the  upper 
cuspids,  but  this,  taken  with  the  compound  curve  on  the  distal  surfaces, 
reproduces  in  a  pleasing  way  the  character  seen  in  the  upper  cuspids. 

Ikdicatioxs.  For  faces  in  which  the  square  character  has  been 
changed  to  the  oval  form  by  the  lengthening  of  the  curves  of  the  cheeks, 
but  in  which  the  chin  is  medium  wide,  enough  so  that  the  tapering- 
form  is  not  quite  suitable. 

A  good  many  faces  lie  on  the  border  land  between  this  form  and  the 
form  illustrated  on  pages  239  and  241,  and  in  some  cases  moulds  from 
any  of  these  forms  may  be  suitable. 


234 


CLASS  I. 
FORM  5— The  Oval  Modification  ok  The  Souare  Type. 


UPPERS 


Mould 
No. 

Length 

Central 

Without  Collar 

Width 

6  aiileriors 

Set  up 

Width 

Kull   U 
Set  up 

Combined 

Bite  and  Shut 

of  Central 

Width  of 
Central 

5   C 

5  D 
5  E 
5  F 
5  H 

LOWERS 


^lould 

I^eneth 

Width 

Width 

Combined 

Width 

Central 

6  anteriors 

Full  14 

Bite  and  Shut 

Four 

No. 

Withoul  Collar 

Set  up 

Set  up 

of  Central 

Incisors 

5  C 

5  D 

5  K 

5  F 

5  H 

235 


loirM    I       ri,A;-S  II. 

'I'luf  mvi'.t'c.  \iit'tii  ol  ilx-  'I  ;ij«;ri/i^  1,yi"'  pf'-'w.'nf^,  »»  ttt<L'  u{>[>c'r  ceii- 
lr(il«,  |(»m'l-Jwlly  wlnii^lii  iipjuoxirrm)  nidc^  which  converge  «o  rapidly 
(Iml-  limy  vvoiiM  Hiiiin-\itiii'.H  unati  ui  iUc  tinddUt  of  the  rf>ot,  and  at  other 
limrrt  III,  llm  ii(«'x  III'  \\ti'.  roof,  TIiIh  Hcvitnt  form  Ik  not  pleaKin^,  but 
wlicii  mo(lili<'<|  hv  ('(iinl)iii;il  ion  with  lh<;  H')iiar<!  or  ovoid  typen,  presents 
Muiiif  III  ilif  iiiu  I  |.l<;i  iiiM  ;iii(|  criVcl  ivc  I'orinK  kiiowu  to  jjorcelain  teeth, 

I'linii  I  111  I  lie  liii-i  ;iii(|  mr>Hl  Hitvi'.vtt  itiodificaiion  of  tlie  tapering 
IVp".  Il  id  i'«'iiiovc(|  n  hull'  riuiii  ilic  priiiiii  iv(;  form  as  may  he  and  lose 
ijiit  nidi'iKiMH  whi"  h  ili;ii  liiriii  pre -ciit  •,  liiii  il  pr<'H(!rv<'H  to  a  remarkable 
(|('|yt;r(Mi  lh(<  H(r«'li,"lli   .iml  i  li:ii:ii  liT  III    llif  ori.'L!  ili;il. 

Tlir  II  |i|iiir-.  iiiiiil  MiirfiK  cs  (d  llir  ii|»|M'i-  rciil  r;i  I,-,  ;irf  iicai'ly  straiirht, 
Iml  llir  ,li"lii  iiiii\r\iiv  nl  ihc  iin'siiil  siirrjifcs  ;iii(|  llic  just  noticeable 
tjiiiililr  (  iii'\r;i  III   llir  (ji'iliil  si  II' liu-cH,  s;iV('  I  he  Icclli    Iroiii   hlockijioss. 

riic  ii|i|nr  l:ilri:il  ;iiii|  cii^iiiifls  nrc  ^Irmijiiv  coiiV(!X  oil  llu;  mesial 
Hiii'l'iHt'M  mill  IkiiIi  |iir,tiii  nil  llir  (jishil  ,siii'l'iiO(!H  the  sanK!  compound 
iMll'NTH  Hj'cii  III  llic  cciil  ni  Ih.  'These  I'lii'ves  iire  (|ulte  (liller(!iit  in 
ehii  I'm  let'   ri'inii   lliuse  seen    in   llie   luriiis   in   ('hiss    111. 

The  lower  incisoi'M  are  cil  like  cha racier  wilh  lh((  uppers.  The 
iiieiiiiil  a  |i|iiii\  I  ma  I  surfaces  are  slii^lillv  cmivex  and  tapcM'  to  necks  luir- 
immiim:.  in  wullli  willi  llie  ii|i|m'I's.  I'lie  dislal  ajiproxiinal  surfaces  are 
hIIj^IiIIn  (imca\e  and  sa\t'  llie  leelli  ti'imi  an  appearance  ol  straiii,htuess. 
The  lower  I'lispids  are  of  lik»'  forms  wilh  llie  incisors. 

I  M'i«  \  I  111  \s.  These  leelli  are  indicaled  for  faces  which  taper  by 
sli'iiiu'hi,  liiiii  lines  lo  chins  sonielinies  of  less  than  uunliuui  width.  Tn 
uumv  cases  ihe  tlilTerence  in  widlli  ol'  llie  chin  will  delerniinc  whotlier 
ji  form  from  this  class  or  one  from  the  stpiare  class  is  iiidicat(Hl,  the 
wide  ihiiis  callii\u'  lor  llie  si|nare  leelli. 

Tills  is  one  ol  the  iorms  in  leelli  which  is  inncli  more  pleasini;'  in 
ihe  monlh  ihan  oul  (d'  il.  The  medinni  si/.i's  will  hi'  found  Iniruiouiou.^ 
with  the  i\  p(*  (>f  f{\ct*  idUMi  spoken  o(  as  "The  .Vuierican  TJusiuess  Plan's 
b'nce,"  wilh  its  a]^pt"aranc»'  o\  clean  ciu  sireuiith. 

Tcelh  o(  ihis  f(>rui  ai'c  likelv  lo  i^row  into  i^rcar  favor.  'Thcv  should 
be  stM  w  ilhoui  ovtM'liippiiiii"  o\'  the  laterals. 


'36 


CLASS  ir. 

MODIFICATIONS  OF  TAPERING  TYPE 
FOUR  FORMS  IN  GRADED  SIZES 


FORN[   1  — The  Severe  Modification  of  The  T.apering  Type. 


f 


LTPERS 


width  14 

Set  up 


IZO. 
122. 


Bite  and  Shut 
of  Central 


9.5 
9.5 


Width  of 

Central 


LOWERS 


Mould 

No. 


L 

M 

N 

r 

R 

Length 

Central 

Without  Collar 

Width 

6  atitcriors 
Set  up 

42. 
44. 

Width  14                Combined 
<^t  iiT»              Bite  an.i  shut 
^'  "P                  of  Central 

Width 

Four 
Incisors 

'             10. 
10. 

I 

112.                      8.5 
lU.                     10. 

26. 
27. 

237 


FORM  2  —  CLASS  II. 

This  is  the  second  modihcatioii  of  the  Tapering  Type  and  is  a 
little  fnrther  removed  from  the  severity  of  the  typal  form  than  Form  1. 
The  approximal  snrfaces  of  the  upper  centrals  are  niore  convex  and 
turn  apart  more  at  the  necks.  The  distal  approximal  snrfaces  show 
more  of  a  componnd  cnrve  and  altogether  the  teeth  are  less  straight. 

The  laterals  and  cnspids  carry  out  the  character  of  the  centrals 
so  that  the  appearance  of  the  npper  anteriors  is  even  better  expressed 
bv  all  of  the  teeth  than  in  some  of  the  other  forms. 

The  lower  incisors  do  not  show  quite  as  much  departure  from  the 
straight  form  as  do  the  uppers,  but  they  serve  as  beautiful  and  charac- 
teristic bases  for  the  uppers.  The  mesial  approximal  surfaces  are  con- 
vex, but  do  not  turn  quite  so  much  apart  as  in  the  upper  teeth.  The 
distal  surfaces  exhibit  the  same  compound  curve  as  in  the  uppers.  The 
necks  are  fairly  wide. 

The  character  of  the  lower  cuspids  is  identical  with  that  of  the 
incisors  except  that  the  distal  angle  is  more  pronounced. 

IxDiCATioxs.  This  form  is  particularly  suited  for  masculine  faces 
of  less  strength  than  those  requiring  Form  1  and  for  some  feminine 
faces  of  the  tapering  type. 

The  beauty  of  these  teeth  is  increased  by  setting  the  upper  laterals 
to  overlap  the  centrals  when  conditions  warrant  it. 


238 


CLASS  II. 
FORM  2— Second  Modification  of  Tapering  Type. 


UPPERS 


Mould 
No. 

Length 

Central 

Without  Collar 

Width 

fi  an  tenors 

set  u\> 

width  14 

Set  up 

Combined                „.-j^,      <• 

Hite  and  Shut             A\idth  of 

of  Central                   Central 

L 

2  :m 

2  N 

2  P 

R 

8.75 
9.75 

10.50 

41. 
44. 

47-48 

103. 
106. 
111. 

8.                         7. 

8.  7.5 

9.  8. 

LOWERS 


I.enjrth 

width 

width  14 

Combined 

width 

Ceutral 

(i  anteriors 

Set  u]) 

;!ite  and  Sliut 

I'our 

Williout  Collar 

.Set  up 

ol  Central 

lucisors 

L 

2  M 

8. 

33. 

99-100 

8. 

20. 

2  N 

9. 

34. 

102. 

9. 

21-22 

2  V 

10. 

37. 

108. 

9.5 

23-24 

R 

239 


FOKM  3  — CLASS  II. 

This  form  is  the  third  modi  tication  of  the  severe  typal  form,  and 
is  somewhat  softer  in  outline  than  Form  2.  The  mesial  approximal 
surfaces  of  the  upper  centrals  and  laterals  show  convex  curves,  but 
these  surfaces  are  not  so  straight  up  and  down  in  the  incisal  thirds  and 
turn  more  widely  apart  at  the  necks,  leaving  wider  interdental  spaces. 

The  distal  surfaces  do  not  show  the  compound  curves  of  Form  2  but 
are  gentlv  convex  from  cutting  edges  to  necks. 

The  curves  in  the  mesial  surfaces  of  the  cuspids  are  quite  different 
from  those  in  Form  2,  being  more  nearly  straight  but  with  a  slight 
tendency  toward  a  double  curve. 

The  lower  anteriors  are  much  like  those  in  Form  2,  with  the  dif- 
ference that  the  necks  are  narrower  and  the  interdental  spaces  are  wider. 
The  cuspids  are  straighter  in  character  than  in  Form  2. 

Indications.  This  form  and  I'\>rm  -t  are  particularly  suited  to 
feminine  faces  of  the  tapering  type.  These  faces  are  often  very  beauti- 
ful. They  have  been  selected  by  many  great  masters  as  the  subjects  of 
their  paintings,  and  they  have  always  commanded  admiration. 

This  form  will  be  found  suitable  for  many  such  faces,  as  well  as 
some  male  faces. 

The  upper  laterals  may  well  be  set  to  lap  the  centrals. 


240 


CLASS  II. 
FORM  3 — The  Third  Modification  of  Tapering  Type. 


UPPERS 


Mould 
No. 

LeiiK-th 

Central 

Without  Collar 

Width 

b  anteriors 
Set  up 

width  14 
Set  up 

Combined 

Bite  and  Shut 

of  Central 

width  of 
Central 

L 

:m 

3  N 

9.75 

45. 

105. 

8. 

8. 

3  P 

10.50 

50. 

124. 

8.5 

8.5 

R 

LOWERS 


Mould 
No. 

l.eiiBrth 
Central 

With 

(j  anteriors 

width  14 

Combined 
Bite  and  Shut 

width 
Four 

Without  Collar 

Set  up 

of  Central 

Incisors 

Iv 

M 

3  N 

92 

36. 

103. 

9. 

22. 

3  P 

92 

38. 

114. 

8. 

25. 

R 

241 


FORM  4  — CLASS  II. 

Tlie  softest  modification  of  the  tapering  type  and  exliibiting  the 
greatest  modification  of  the  original  form  by  combinations  with  Types 
1  and  3. 

The  mesial  aj)proximal  surfaces  of  the  upper  centrals  are  decidedly 
convex  and  begin  to  separate  at  the  incisal  edges.  They  turn  apart 
quite  a  distance  and  leave  a  rather  wide  interdental  space.  The  distal 
approximal  surfaces  exhibit  marked  compound  curves. 

The  laterals  show  much  more  strongly  than  the  centrals  the  modi- 
fying influences  of  the  other  types  of  teeth.  Both  approximal  surfaces 
are  convex,  and  the  compound  curve  seen  on  the  distal  of  the  centrals  is 
not  in  evidence.     The  cuspids  are  more  like  the  centrals  in  character. 

The  lower  incisors  express  strongly  the  character  seen  in  the  upper 
centrals,  the  compound  curve  on  the  distal  approximal  surfaces  giving 
them  much  character.  The  lower  cuspids  are  rather  straight  but  have 
well  defined  distal  angles. 

Ijstdications.  This  form  is  well  suited  for  feminine  faces  which 
taper  from  eyes  to  chin  by  soft  curves,  often  quite  rounding.  It  is  par- 
ticularly suited  to  the  character  of  faces  seen  in  illustrations  and  in 
great  paintings  and  typical  for  beauty.  The  laterals  may  be  set  to  lap 
the  upper  centrals  slightly  which  increases  the  beauty. 


242 


CLASS  II. 

Form  4. — The  Fourth  and  Softest  Modification  of  the 
Tapering  Type. 


TRUBYTE    FORM  4     CLASS  H 
SIZES  AS  MOULDS  4L-4M-4N-4P-4R 


..jnim 


UPPERS 


Mould 

Length 
Central 

Width 
6  anteriors 

Width  14 

Combined 
Bite  and  Shut 

Width  of 

No. 

Without  Collar 

Set  up 

Set  np 

of  Central 

4  L    . 

4  M 

S  75 

41. 

9S-99 

9. 

8. 

4  X 

9.75 

44-45 

106. 

4  P 

4  R 

LOWERS 


Length 

Width 

Combined 

Width 

Central 

6  anteriors 

Bile  and  Shut 

l'"our 

Without  Collar 

Set  up 

Set  up 

of  Central 

Incisors 

4  L 

4  M 

9. 

31.5 

95. 

9.5 

19.5 

4  N 

9. 

35. 

103. 

9.5 

11. 

4  I' 

4  R 

1 

243 


Form  1 — Class  III. 

When  the  description  is  published  in  The  Dental  Digest 
it  may  be  placed  here. 


244 


CLASS  III. 

MODIFICATIONS  OF  THE  OVOID  TYPE 

FOUR  FORMS  IN  GRADED  SIZES 


FORM  1 — The  Severe  Modification  of  The  Ovoid  Type. 


UPPERS 


Mould 

No. 


Length 
Central 

Without  Collar 


Width 

6  anteriors 

Set  up 


Width 
Full  U 
Set  up 


Combined 

Bite  and  Shut 

of  Central 


Width  of 
Central 


1  T 

1  U 

1  W 

1  X 

1  Y 


LOWERS 


Length 

Width 

Widtli 

Combined 

Width 

Mould 

Central 

6  anteriors 

luill  14 

Hiteand  Slmt 

I''our 

No. 

Without  Collar 

Set  up 

Set  up 

of  Central 

Incisors 

1  T 

1  U 

1  W 

1  X 

1  Y 

245 


Form  2 — Class  III. 

When  the  description  is  published  in  The  Dental  Digest 
it  may  be  placed  here. 


246 


CLASS  III. 
FORM  2 — TiiK  Skcoxd  Modii  icatiox  of  The  Ovoid  Type. 


UPPERS 


Mould 

No. 

I^enietli 

Central 

Without  Collar 

Width 

6  anteriors 

Setup 

Width  14 
Setup 

Coiiil>iiie<l 

liiteaiid  Shut 

of  Ceiitralv 

Width  of 
Central 

2  T 
2  U 
2  W 
2  X 

2  Y 

. 

LOWERS 


.,     t<                      Length                    Width          |        „r:Atu  ^A 

Mould                       Central                 6  anteriors               Width  14 

^"-                  Without  Collar             Setup                     Setup 

Combined 

Bite  and  Shut 

of  Central 

Width 

Four 

InciHJjrs 

2    T 
2   U 
2  W 
2  X 
2  Y 

247 


Form  3 — Class  III. 

When  the  description  is  published  in  The  Dental  Digest 
it  may  be  placed  here. 


248 


CLASS  III. 
FORM  3 — The  Third  Modification  of  The  Ovoid  Type. 


UPPERS 


Mould 
No. 

Length 

Central 

Without  Collar 

Width 

6  anteriors 

Setup 

Width  14 
Setup 

Combined 

Bite  and  Shut 

of  Central 

Width  of 
Central 

3  T 
3  U 
3  W 
3  X 
3  Y 

LOWERS 


-,     ,,                      Lengfth 
Mould           1          Central 

N°-              1    Without  Collar 

Width 

6  anteriors 

.Set  up 

Width  14 
Set  up 

Combined 

Bite  and  Shut 

of  Central 

Width 

Four 

Incisors 

3  T 
•      3  U 
3  W 
3  X 
3  Y 

249 


Form  4 — Class  III. 

When  the  description  is  published  in  The  Dental  Digest 
it  may  be  placed  here. 


250 


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ment with  the  Librarian  in  charge. 

DATE  BORROWED 

DATE  DUE 

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'rJ/IW    rt   r    1 

""  2  X  i 

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1 

C28(|I40mIOO 

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ill''  fe'^'ll 


